a sdd won't improve gaming unless you install the game on it, running windows and a few apps on a sdd only gets windows to boot quicker and run better/faster, if you run it as a cache drive as well for your hdd then you may see improvements in games or if it's a big sdd and can install a small amount of game on it, then it's worth the upgrade, if it's a smaller one then it's not worth it.
don't get me wrong, i love sdd, have 2 x 256gb adata pro's then a 3tb drive im my gaming rig, with some external hdd as backup and storage etc
until they get larger and cheaper atm there more of a Luxury item for most.
for me save your money and buy one of these
http://www.overclockers.co.uk/showproduct.php?prodid=HD-089-OC&groupid=1657&catid=2101&subcat=2199 as at least you get more storage and speeds are very good, still cheaper than 2 x 256 or a 500gb sdd
then use it for o/s and most games would fit you play on a weekly basis, not the whole collection etc
now seeing above post, a better cooler and a free speed boost with a OC would be better and cost far less, then save the rest until you have enough for a good sized sdd or revo etc
