I saw this article today about digital cutters in general:
Digital Cutting Machines Alter the World of Crafts
It says the Silhouette lists at $300, but I got it for around $158 + free shipping online from
Craft-e-Corner. It isn't as cheap right now, but if you can get it for under $200 shipped, it's pretty good. I actually got it from Craft-e-Corner via eBay, so you might want to check the prices there to see if they're any better.