Wait for cowboom to have a sale. I've seen 250gb hard drive S models for 90-100 bucks. I got a Halo Reach Console for $115 a while back. A few days ago they had Reach consoles with two reach controllers for $150. Unless you really need 500gb these are great deals.
Pros: The pills were there. Cons: So was the tank.
You know, it always puzzles me that consoles have had standard USB ports for at least a couple generations now, yet still insist on locking those ports out of the very standards that USB is famous for.
If you buy a USB hard drive, you should be able to plug the damned thing into a USB port, let the system format it and have it be just as useful as something stuck into an internal slot.
Arbitrary limitations- they are aggravating, yes?
It's why you have to buy a whole new console if your disc drive goes out instead of just being able to plug an industry-standard optical drive in. It's why xbox 360 hard drives are ten times the price of "standard" drives.