I'm thinking about buying a 120GB Hard Drive. I'm thinking about buying a USB drive rather than another internal drive. I thought it might be nice and portable. According to NewEgg.com, the price difference is about $20.

Here's my questions:

1. Do these work pretty well?
2. Are they fast enough?
3. Can you run the same kind of defrag programs on them?
4. Any recommendations for Maxtor, WD, etc?

Thanks!