Wow, if you wrote that as your suggestion, you're going to HATE mine!!
Motors: I am using 2 pairs (4 wires) from a CAT5 cable for each of the 5 motors (incl. extruder), they are I think 24awg
Heaters: 20awg
Thermistors: Using more of the 24awg CAT5 strands, just one pair for each of these
Endstops: Using more of the 24awg CAT5 strands, just one pair for each of these
PSU: I'm using a heavy-duty 3-prong cord for the 120v mains run to the PSU, and 2 pairs of 20awg for the 12v run to the ORD (1 pair is for the 5A circuit, the other is for the 11A circuit; my RAMPSv1.4 board has both as inputs and a handy Molex connector on the end)