The ASUS A7N8X deluxe has all you want. As for the Barton 2500, I know 1.83 is weanie, but that is why I said OC the heck out of it, you should at least be able to hit 2.2 ghz. Use A Vantec C7040 cooler, very quiet and very cool. For video Get a Radeon 9500 pro, should be able to get one for close to $150, and it will blow the doors off a ti4200.
Here is an except on the MOBO from newegg:
Model# A7N8X Deluxe Retail
Supported: Socket A AMD Athlon/XP/Duron (support AMD XP3000 "Barton")
Chipset: NVIDIA nForce2 SPP, nForce2 MCP-T
FSB: 333/266/200MHz
IDE: 2x channel ATA133
RAM: 3x 184-pin DIMM Sockets (PC3200/PC2700/PC2100 non-ECC DDR Ram)
Slots: 1x AGP (Pro/8X), 5x PCI
Ports: 6x USB(2.0),
Onboard Serial ATA: Silicon Image Sil 3112A Controller with 2 ports
Onboard Audio: Realtek ALC650 6-ch w/built in amplifier,
MCP integrated 3Com MAC + Broadcom AC101L PHY LAN
Firewire 1394: 2 Ports MCP-T integrated IEEE 1394a + Realtek PHY 8801B Model#: A7N8X Deluxe Review by Gamepc.com
Just noticed you said on-board video, and NO it doesn't have that, and NO you don't want that, you need a good video card like the 9500 pro.
Edit: 9500 pro is $177, well worth it.