With all my respect, prakalejas, this is not true. It makes a huge difference, especially when you have a lot of application installed, all with different start modules, auto-run services and related dll's. For example, on a Vaio VGN-Z11WN (Core2 Duo, 4GB RAM) replacing the original 250GB Toshiba HDD with the Intel 160GB new SSD, the start-up time has dropped from nearly 5 minutes to 40 secundes. Moreover, all apps start faster (I'm talking about having the app up and running, not about seeing its front-end interface).
I have also to add some more details:
1. It is mandatory to use Windows 7 or Vista with the SSD. XP is not using a different policy with the SSD, having imact in SSD reliability. W7 is supposed to be better than Vista, however I could not find any difference between W7 and Vista SP1.
2. The big advantage using the SSD comes from the almost 0 acces time, not from the sustained datarate. The peak datarate is limited by the SATA chip speed. Considering this, the biggest impact will be seen when the applcation or process has to work with more than one file simoultaneously. Windows is a process loading lot of files (dll's, drivers, livraries etc) and if you use multitasking SSD will be a very good investment. How much costs you time, when you wait in front of an unresponsive computer?