The Fusion-io ioDrive (80GB) is really fast---and really expensive---but if you need a lot of performance it's worth the money.
ZDNet Australia has reviewed the Fusion-io ioDrive. If you recall Fusion-io it's a startup that has lined up server heavy hitters like IBM, garnered VC funding and lured the likes of Steve Wozniak as an adviser.
The problem: The ioDrive isn't an enterprise mainstream item just yet. And it's certainly not for consumers (unless you have a big bank account). In a nutshell, if you need lots of I/O performance for local tasks like CAD and video editing, this pup will push a lot of data for you.