You can get 1000 feet of Cat5e on eBay for £40 over here. Then £10 for 100 connectors. You'll love crimping at first, then learn to hate it.
That's pretty nice. =P I don't need THAT much cabling, but yeah, the Ethernet cabling (and the phone cable) is what is limiting me from mounting the entire setup on the wall, high up for good reception.