"Seriously, sometimes I wonder why we bother investing so much in gaming PCs"
depends on your tase, mman74.
if you love old games, then Dosbox & emulators etc. give you more freedom than vconsole, xbla or whatever online paid service they're pushing these days. I didn't buy D3 but still got in the mood to reinstall D2 and it ran natively on my W7 laptop & networked easily with my old win98 desktop for some Lan gaming too, on my 1 copy of the game thanks to Blizzard's generous no-cd patch.
if you like choice of mouse/keyboard/gamepad/joystick/wheel/wired/wireless controllers.
if you like messing around with settings/options/mods/editors
if you're smarter & sometimes crave for something smarter. too many examples of famous-name games dumbed-down for gamepads & tvs. baldu'rs-gate diablo-clone on consoles?
if you loath unskippable intros/titlescreens and know which .bik files to delete on PC
if you loath online interruptions/updates/hellos/popups/DRMs/loading-times and crack the games you legally own
expensive?? IMO there's been no significant cpu advancement since core2duo, nor any significant 3d-card advancement since radeon 5850 (or it's equivelant geforce), so you don't need the latest hardware. don't be hyped by rediculous 2048x1024 benchmarks. any game'll run smooth on a cheap radeon-7750 if you just realize that playing higher than 1024x768 really doesn't make much difference.