Dual G4 PowerMac

Ok, so I'm still deciding on whether or not to buy my Mac, after selling the way too powerful for me Dual 2ghz G5 PM. I'm deciding between a Dual G4 or an HP machine (http://www.pcmag.com/article2/0,1895,1848866,00.asp). I'd be buying the refurbed HP for just $759 after $50 rebate and instead of integrated graphics, it has a low-end ATI X300SE video card, not great, but not integrated either. I'm a college student who does a little audio editing/mixing. I like to use SOund Forge and Adobe Audition, both PC products, but I could use something for the Mac if I go back. I'd like to get this system for under $900. Could I find a Dual G4 for under 900? And have it be comparable to the HP? I'd really need a PVR card or external firewire for it as well, this is something the HP comes with. So budget that in for the Mac. I really like OS X too. Would the G4 dual be good enough for Tiger? I could upgrade video card to anything really couldn't i? I'm seriously considering the PowerMac, but the HP has got many things going for it as well.

You could probably get a used dual 800/867MHz G4 for $900. (Which would run Tiger just fine, incidentally.)

But compared to a dual-core Pentium-D 820 PC? No contest. The PC would be much faster. Unless you really like OS X, I'd grudgingly suggest you get the PC.

Here is a really weird suggestion, but something to consider:

466 MHz Digital Audio Power Mac (~$300-400)
Dual processor Upgrade (1GHz=$400 or less)
Radeon 9600 (~$120)

Any of these could be had for less if you look for bargains on eBay. Just a thought.