If you can afford it the 256GB model is even better. You really need to keep 20% of an SSD free so TRIM can work correctly. With an 120GB model that comes out to about 22GB since the drive wll be 111GB when it's formatted.
The 60gb drives are starting to become not as worth it as the 120gb drives. You can get a vertex 3 120gb for $90 if you look hard enough. Get that for OS and applications. And another one for games, perhaps a larger one. I currently run an ocz vertex 3 120 just as i suggested and an older vertex 2 240gb for games. The setup is plain awesome. I also have a network storage pc i put together with FreeNAS though for storage, it has a 2tb mechanical drive. You could do something siwilar using just a usb drive.