Only updated this a while ago, being a router I didn’t need much in the way of power, just reliability. So its mainly made of old parts.
Generic Desktop ATX (horizontal) ‘modified’ to *erhem* fit the power supply =D.
ASUS M2N SLI Deluxe
AMD Sempron 140 2.8GHz (underclocked to 1GHz) 45w Single Core, unlocked to Dual Core with NVIDIA Unleashed mode. Shows as AMD Athlon(tm) II X2 4400e.
Western Digital Caviar SE 160GB | SATAII
Western Digital Green 2TB | SATAII
2x 1GB Corsair XMS2 DDR2-800
Vantec ION2 CAN460-C 460W
ExpertColor S3 Trio64 86C764X 8MB | PCI
Its running IPFire, which is actually software based on the first Linux router/firewall distro I ran (IPCop) which was really nice, except it only ran Linux kernel 1.4, which is rather old and lacks many features.