All the wires from psu are already sleeved, all the little wires though, I hide behind where the 3.5" bays are.
All IDE cables are already sleeved too, alot of wires coming from the fan controller at the top, I stuffed them all above the dvd drives, and kept em there with a few ties.
I tied temperature sensors to a close by IDE/power cable to keep it together.
I dunno, weaed the northbridge cooler's wire between some capacitors.., wrapped some wrap around some usb wires.., and like, you see the rear case fan, follow that wire and it actually goes under the sound card to a 3pin connector just under there, its just so it's not so visible and knocking around. It's fairly tidy, though the thick wires, they do kinda form quite a mass in there.
Oh and a modular psu, so I don't have to have everysingle connector the psu comes with, attached.