http://www.pinnaclesys.com/PublicSite/u ... +Stick.htm
These are the best out there. I have the one I linked to but there are 4 tabs on the left to different ones that'll work well for what you need. Pinnacle is the best for that stuff. The one I have goes through USB so I can use it on any of my computers. I use it on my laptop 99% if the time though. Comes with a program with a guide and whatnot like a media center dvr etc... good stuff!
As for the quality... picks up HD local stations easily and then some if you use the antenna. You can run your cable line right into it. The picture and quality is probably better than your tv just because of the sheer pixel count.
edit: it can also run through your vista or windows media center if you don't want to use the pinnacle program.