It's a very sound plan. I'd go with the 60GB drive and try to put your home folder there as well, since browsers place all of their temporary and cache files in the home folder tree. Having them on the SSD will speed up your web browsing as well. You can put your data files on the hard drives for bulk storage.
If you have enough RAM so that the game can be loaded entirely into memory then the only real effect of putting your games on the HDD instead of the SSD will be slower loads, and perhaps slower scene changes if the game has to wait to load new scene data.
If you don't have enough RAM then you might be better off spending your money on RAM first and an SSD second.
6GB of RAM is probably plenty. Try to configure your system so that you have empty DIMM slots on your motherboard. For example, if you have a motherboard with 6 DIMM slots, buy three 2GB DIMM modules, not six 1GB modules. That way it will be easy to upgrade later if you want to.
And of course you'll need to use a 64-bit OS to take advantage of all that RAM.