Well, I hear it is advisable to only fill about 80% of the capacity of the SSD, or else it degrade the performance. Not something I can back up with a link, maybe someone can help me out, its just something I have heard around.
I am like you in that my SSD (when I decide on it) will mainly be for my OS and a few games like ArmA, BF2 Project Reality, and maybe a few steam games. I can see me hitting maybe 100gb of stuff MAX, bearing in mind W7 64 is around 20gb in size. I have been waiting for the OCZ Vertex 3, however I am tempted to just get the Intel 510, due to its reliability, and it will still be damn fast.......Will wait another week max maybe.