I would do a FRESH install of Windows 7 with Solidworks on the SSD. This should increase performance and speed. Don't worry about your Solidworks files, You shouldn't be using those soo much that it would make it worth putting them on the SSD. If you have any projects the you spend most of your time working with, You may want those on the SSD too, just to keep it moving quick!
I was sorta expecting the fresh install solution. Is there a way with Win 7 that I can do a clean install without having to reinstall all my applications? It's the reinstalling that is the biggest pain...
Depending on how large your CAD files are, having your ACAD and the files on the SSD will dramatically help you speed up your use.
When dealing with large CAD files that have 100's or 1000's of XREF's, MODELS, etc... they can take minutes to load. Not to mention minutes to save (which I'm sure you do as often as I do). Having all of the files on the SSD will cut down on this a lot. If you are running into issues where you are running out of space, you can always move a project over to a storage drive once it has been completed.
I purchased a 60GB SSD awhile back and noticed a huge difference in performance when I was using all of my CAD files off of it. I just wish I would have purchased a large one at the time.