4Chan Beckons You…
The learning curve can be a bit steep, so you will likely need some help along the way. Deviant Art and Rainmeter are the two default forums for Rainmeter questions, and many of the artists who create skins can be found hanging around those forums, answering questions and taking bug reports.
If you are feeling brave, you'll find 4Chan's /wg/ group helpful as well, if you can take it. While /b/ gets all the notoriety, there's more to that site. The /wg/ group, General Wallpapers, has some great threads where people post art collections for use as desktop wallpapers. My wallpapers folder image count is over 200 (but not quite over 9000), and all of them are from /wg/.
There's also plenty of Rainmeter talk, and people will post screen caps of their desktops asking for advice. This being 4Chan, you better have a thick skin. You'll get some helpful advice and probably a little abuse along the way. Those boys play rough.
There is a sticky message at the top of the board with information for newbies to read before asking common questions. There is also an image to view with advice, so really read that first. I take no responsibility for the verbal flogging you get for not RTFM'ing.
Between ObjectDock and Rainmeter, you can make your Windows box completely unique and look nothing like a generic Windows PC, with just a little work.