Both Compaq and Dell used to weld parts in, but that practice is over, so far as I know. Dell's big thing is using non-standard parts, so that upgrading is a nightmare. They even use their own spec of power supply, so don't even think about putting in a new mobo.

I Buy Power uses standard parts, and there's no welding involved. I can attest to this personally; I poked around inside my friend Ben's PC after he bought from them. And Ben has replaced both his proc and mobo with no problems, so there you have it.

I can't speak to everybody else. I'm sure if you buy a custom watercooled Voodoo PC you won't want to do any upgrades yourself. Don't know about Alienware and Falcon Northwest. But those guys also charge buckets of cash for their PCs, so I wouldn't be leaning their way anyway.

I can attest to I Buy Power being geek and upgrade-friendly, but I'd like to know about more places. Anybody have any experiences they can share?