I've used Ubuntu 5.04 before on my laptop, which has a VIA C3 CPU, meaning that i had compatibility issues with Fedora, so i'd say you can rely on it for almost any machine.
Programs are easy to install on it too, so it's quite a good distro for beginners, but Linspire was better imo, however, that costs a hell of a lot of money, so i wouldn't go for that.