Feature - Firefox 3 is scheduled to be released at 10 am PST today and if the organization’s Download Day website is any indication, then you may have to wait in line until you get the installation file: 1.6 million people have signed up to download their browser today. Here are our top 10 reasons why we like the new browser why we believe you should upgrade to Firefox 3 soon.

Most of the browser’s 15,000 changes are evolutionary modifications and when you launch it for the first time you will, despite a few visual changes, immediately feel at home if you have used Firefox before. But there are some dramatic changes, tweaks and refreshed features that we believe will improve the overall browsing experience and productivity. Expect to see improvements in many key components of the browser, including the bookmark manager, the download manager, the address bar and back button, add-ons, passwords and, most importantly, in security, reliability and performance.

Here are our top 10 reasons why you should upgrade to Firefox 3:

1. Overall speed. Much more performance across the board is the key reason for an upgrade. The overhauled Gecko 1.9 rendering engine and significant code tweaks and optimizations contribute to significant speed gains. The browser launches and runs faster and feels much more responsive, especially with multiple tabs open at once. Web pages load substantially faster than in Firefox 3 and in early beta version of Firefox 3. We are also promised less crashes.

2. A tuned JavaScript engine. Optimizations to the JavaScript interpreter is currently the main battlefield in the browser speed race. The JavaScript scripting language is widely used on many web 2.0 sites and web applications, acting like glue between the user interface and the main program logic on a server. Mozilla worked on its SpiderMonkey technology powering the JavaScript interpreter, revealing speed gains almost immediately. Web 2.0 sites load faster and web applications many of us use every day (such as Gmail, Yahoo Mail, etc) are much more responsive. Mozilla claims that Firefox 3 is 2.7 times faster in JavaScript than Firefox 2 and 9.3 times faster than IE7.

3. Improved memory handling. Firefox 2 was plagued with memory leak problems that led to system memory fragmentation when shutting down the browser: The issue was that the browser failed to return allocated chunks of memory. Firefox 3 finally solves this problem, delivering more efficient memory handling that results in far less memory leaks and optimized memory use, especially when multiple tabs are open.

4. Stronger phishing/malware protection. Firefox 3 comes with improved filters and optimized protection against phishing sites, malware, cookies and other techniques that compromise your privacy and security. Phishing is an elaborate technique designed to deceive user into pixel-perfect clones of established sites such as Paypal in order to obtain login credentials or other critical user data. Firefox 3 checks each site you visit against Google’s large, continuously updated blacklist of known phishing sites. It will show a more prominent warning when you encounter a known site that is known to install malicious software and is configured to hide the content of a known phishing site by default. If you download an executable file, the browser will send a note your anti-virus software. New to Firefox 3 is Extended Validation SSL (EV) certificate support, which guarantees the identity of the individuals running a website. When you visit sites like PayPal, look for a green logo in the address bar to check the owner of the site and see if the connection between your browser and the site is protected from eavesdropping.

5. An address bar with brains. The Address bar is not just the place to type URL anymore. Firefox 3’s address bar, now dubbed the Smart Location Bar, makes it easier to find the sites you recently visited, take you to stored bookmarks and bring up a certain tag or a page from your browsing history. All you need to do is start typing first few letters of the content, not just the site’s URL. The bar learns through repetition, so the next time you start typing "fi," it will remember you’re looking for Firefox, not Finland. When you start typing, the results appear immediately, formatted more prominently in two lines.

Read on the next page: Upgrade reasons 6 -10

6. Pimp your bookmark manager. The Places Organizer has replaced the old Bookmark Manager in Firefox 2. You can organize your bookmarks more efficiently, since the revamped interface has a crisp interface and offers multiple view and sorting options. You can search your bookmarks using Boolean rule searches and multi-column results. Frequent Google searches can be saved for later quick access through the address bar. You can create and restore full backups containing all your bookmarks, tags and your browsing history. Bookmarking is now done by clicking on a star icon in the address bar: Click once to bookmark, click again to bring a convenient drop-down menu to name the bookmark, file it under a folder and add one or more tags. And yes, you can attach one or more tags to your bookmarks to associate a user-defined keyword with bookmarks. Tags enable you to sort bookmarks by topic, which isn’t possible with the old-school bookmark categories limited to only one per bookmark. New to Firefox 3 are also smart bookmarks that are automatically filled according to a certain criteria, much like iTunes’ Smart Playlists. The three default smart bookmarks offer one-click access to your recently bookmarked and tagged pages and most visited sites (you can create your own as well).

7. Updated Download Manager. The basic download manager from Firefox 2 is finally revised and has become much more useful. Its reorganized user interface makes it easier to locate downloaded files and see the name of the website where a file came from. The browser status bar now always shows the total and remaining download time. Finally, you can resume canceled downloads after a crash or restart. Yes, there were add-ons for Firefox 2 with these capabilities, but it’s nice to see these features becoming default built-in browser capabilities.

8. Unified looks on every platform. The new Firefox 3 brings a fresh design and an updated look for all platforms. At first sight, browser may seem to be very similar to the preceding Firefox 2. However, a closer look reveals subtle differences, such as more attractive blue-back and forward buttons. Within days of usage, you will discover many thoughtful design tweaks that improve your experience and amount to a big overall boost in usability. Overall it appears that GUI design was taken much more seriously than in previous Firefox generations: For example, the back button is bigger and easier to click. But it is only highlighted next to the address bar if there is a page to go back to. Previous Firefox versions were wrapped in Mozilla’s own look and feel that didn’t follow operating system guidelines. This has been particularly annoying in OS X where Firefox oddly stood out with its noticeably different design. In Firefox 3, the GUI designers followed operating system guidelines to make the browser a part of the general application environment.

9. More powerful add-ons manager. A great extensibility is one of the most important contributors to the Firefox success story as users can add new functionality by installing third-party extensions, add-ons, plug-ins and themes. Firefox 3 has a tweaked add-ons window that is more intuitive and user-friendly. You can now disable third-party helpers (Flash, QuickTime, etc.) in the new plug-in manager. The updated adds-on manager makes it possible to search and install extensions and themes from within the interface itself - no browsing required. You should be warned that there is a high probability that your set of extensions will not work with Firefox 3 since updated versions are not available yet. Luckily, whenever you fire up Firefox 3, it checks installed extensions to detect possible incompatibility problems, turns off incompatible ones and checks for an updated versions in regular intervals.

10. True zoom. There is a lot of space on these new HD displays with enormous resolution capabilities - why not take advantage of it? The new zoom function in Firefox 3 means a world of difference as it increases the size of all the elements that make up a webpage, not just text. Text, surrounding graphics, CSS elements, interface elements, it all grows bigger as you zoom in, with images smoothed as they’re rescaled.

Want to chime in? Tell us what you think about Firefox 3 and leave a comment below.