It depends an awful lot which game(s) you're talking about, but if the program and all of its data files are on the SSD then I'd be very surprised if it didn't load at least 2-3X faster than it does off a hard drive.
Once it's loaded into RAM and started playing, though, you're not likely to see a lot of difference.
SSD won't help FPS.. but level loads , bootup speed, and basic navigation throughout ANY of the system's GUI will be MUCH improved.
Better to get a larger one, such as a 120GB version, than a smaller 64GB as W7 will take afair amount of space unless you start tweaking it to have a smaller footprint(such as reducing swap file size.. disabling/deleting th hibernation file.. and sutting off/downsizing system restore).
SSD is awesome and most say they will never go back after using one for a little while. Some even say they feel like a system is broke when they go work on one that has HDD as a boot drive. The harder you use the system?(as in multitasking).. the more you love these things. Good luck on the hunt.
One quick thing though, I do buy one, how would I go about moving Windows 7 to it? Would I have to do a clean install?
A clean install is the recommended way.
If reinstalling everything is a problem you can clone from the old drive to the new drive. I've done this twice, once with Norton Ghost (had a lot of problems with it) and once with Easeus Total Backup (very quick and easy). After cloning just put the SSD in place of the old drive.
Yes.. fresh is always best.. but just be sure to clean up all the trash first and even run a good old defrag on the HDD filesystem before cloning the image over to the SSD if you do go that route. Some clone/image initially with intent to install fresh at a later date as it buys you time(if no issues arise from it of course).
Also be sure the HDD is running in AHCI mode already. If not then do the reg changes to get it running in AHCI mode before making the image.
AHCI mode will bring extra speed from NCQ support and better caching as well. That's why all the SSD mfgrs recommend it these days.