Best PC Motherboard

What is the best motherboard for a PC running AutoCAD and other various engineering/architectural software? The rest of the PC specifications are as follows: Intel Pentium III, 128/256 mb RAM, ATI (Rage 128) AGP graphics card, 10-12 GB HDD, 3COM (3C905B-TX) NIC.

When I say “best”, cost is not a factor, but reliability, expandability, functionality, speed and longevity are the important considerations. The built-in BIOS could also be a factor. I’m looking for brand names and model numbers if you have them, and any other thoughts that this question might inspire.

Thank You.