I'd skip the PS2. It wasn't good when it came out and it still isn't good.
OTOH Dreamcast IS a good buy actually

I don't regret having to pay 150 for it, let alone 80.
PS2 was pure laziness, I'd wait to see how the Xbox and gamecube fair, and there's a great chance they'll be better than Sony's shortsigthed effort of the Ps2
(And to dismiss any bias, there is a PS2 in my house right now [roommate] and I think it sucks after watching/playing it)