Corsair, Crucial, Intel, OCZ are probably the better makes of SSD.
There's not much to look out for, except that some manufacturers provide a set of utilities for managing your SSD (there's more involved in keeping its performance optimised than there is with a regular hard drive). That said, W7 natively manages SSDs much better than earlier operating systems.
As for uses: the real benefit of an SSD is the speed with which it can load programs, including your operating system, so you should put your OS and e.g. MS Office on it. Put your data on another drive.