The first time you use your computer with the SSD set to SRT you won't notice much of a difference. Over time it will speed up your system more and more (with common tasks). Eventually common tasks will perform virtually the same as though the OS and associated apps were installed directly on the SSD while other things will at worst perform at the basic HDD speeds. The big benefit is that you won't need to worry about fitting everything in, in only 60GB. The system can worry about it for you.
Check out the following video: http://www.youtube.com/watch?v=U83ED4FOWiw