I would like a SSD to hold the OS and my most frequently used programs. However I can't justify paying so much for such a small drive. With 4GB of RAM, Superfetch, automatic defrags etc., Vista is optimized from the ground up to hide the poor performance of mechanical hard drives, resulting in acceptable performance with any mid-range 7200RPM drive or better.
Now that the problems of high write latency and poor random write performance have been more or less solved there are no disadvantages to a SSD except for cost per GB. One major advantage is that flash-based drivers tend to fail in a predictable and graceful way. When a cell fails, it's simply marked as bad and the data is written to another one. Also, the cells tend to fail on writes, not reads, so your existing data is safe. When my 74GB Raptor failed on the other hand, it just started making weird noises and 10 seconds later all data on the drive were lost for good. That would be extremely rare with a SSD but it's how hard drives usually fail.