Here's my (rather bargains, £200!) Mac Pro (1,1). Not my first foray into the world of Apple, I've also got a rather ageing MacBook (2,1), and I've owned various iPods and iPhones too. But this is certainly one step above.
I've upgraded it a touch, with two Quad-Core Xeons (Incorrectly reported as 1.86GHz 1066FSB, as I've BSEL modded them so that they are now 2.33GHz and 1333FSB. Bootcamped Windows 7 reports them correctly, so I know all is well, and PowerFractal numbers confirm the real performance in OS X). It's also got 4 500GB HDD's in two RAID1 arrays (software unfortunately, no hardware RAID card in this one), 22GB of RAM (4x 4GB, 2x 2GB and 2x 1GB), a Radeon HD5770 1GB (PC version, flashed with EFI ROM), and I've also added the bluetooth and airport modules.
All in, I've spent around £325 on buying and upgrading the Mac Pro, which I feel is decent enough value!