So unless you're running Linux, I recommend NOT going with 60. I do recommend SSD, however. It will be the best speed boost you can get shy of upgrading CPU and a major video card upgrade.
I picked up the 128GB SSD.
I actually hate the fact that I have to get Windows. I've been using Ubuntu now for a few years and love it.
I'm building a Windows machine for games. However, I may get a second cheap 60GB SSD for a Linux dual boot.