I have an external USB Lite-On, sounded like a dying car at first but now it's quieter (setting it on a couch arm instead of a desk silences it too), so I've experienced the Lite-On noise. It's fine, it doesn't give me a headache or anything... and I've heard it a lot, I've used it on USB 1.1 ports which make things take forever.
Alright, hopefully I can make it to Micro Center, haven't asked yet (we'll be going that direction next weekend, so I may get there then).
Never actually put a PC together, but I have played around inside them and handled most of the parts. Main worries are the motherboard and heatsink, they sound a little tricky and I've never done them before (other than on old heatsink which I think is different), but we'll see when I have them.
Again, thanks everyone.