G4 is 1.25 ghz is slower than a 3ghz p4. Hands down. Also, emac's are heinously ugly, and if you want to wait for the right deal, you can get that dell for about 600 bucks with a free LCD panel.

I'm not going to argue that OS X is anything but awesome, but please... PC's are still way cheaper, not at all harder to use, much more expandable, and have far more available software.

Also, neither of those computers is going to perform well with only 256 megs of RAM.