Get an IBM, much lower failure rate. They cost more than OCZ and are a little slower than some of the other SSDs, but not enough that you will notice it in the real world. OCZ can be a real pain, and then you can end up spending more money on another one
I will not get too technical here, but, I use 2 hard drives. I normally use Western Digital Black 640GB, however, I could not find them recently, so, they may no longer be sold. Check Newegg.com
I partition each drive with about 100GB on the outer edge of the platters [1st partition], the first drive being used for the OS [Windows operating system] and the partition on the second hard drive for games.
This uses the fastest portion of the hard drives, and both drives operate indepenently of eachother, so, there is no overhead to speek of.
This is not as fast as an IBM SSD, so, if you find one as cheap as a hard drive, get the SSD for the OS and games. Dump everything else on the second drive. You can even put other programs on the second drive, those that do not matter so much as to how fast they manipulate data.
This is not a complete discussion of drives, but should be enough to answer your questions.