I make an effort to keep my wires and cables neat and orderly, and while my computers are nowhere near Voodoo's caliber, I've learned a few tricks.
As other people mentioned, fold the IDE cables so they lay flush with the sheet metal of the case, and use whatever folds and creases necessary to work the cable around the case and up to the connector. Also, most people know that zip ties are a godsend. I use them liberally, sometimes to leash a stray wire to a part of the case. Also, I use electrical tape to wrap up wires that have been folded. For example, the ATX motherboard power connector, with all of its 20 wires, can really be a PITA. I fold it back on itself, and then back again, if that makes any sense. It's like folding a piece of paper into thirds. I do that, and then wrap a zip tie around it to keep it there, and then encase it in electrical tape. It looks spiffy and does a really good job. I much prefer it to wire loom.
Sometimes you have to lengthen or shorten some wires. This is easy to do with PSU wires and floppy cables and 40-pin IDE cables, but 80-pin IDE cables are damn near impossible to muck with.