I've got a similar setup, here's the details:
Athlon XP 2200+
Asus A7N8X Deluxe 2.0
OCZ PC3200 DDR (256 x 2, Dual Mode)
ThermalTake Volcano 9 (OCZ Silver thermal paste)
ThermalTake Smart case fans (front and rear)
Heat sink on the Northbridge (attached with thermal tape)
Deer 300w power supply (cheap, but AMD approved)
Rounded IDE and floppy cables
The best I've been able to get so far is 1.921 Ghz stable (166 FSB, 11.5 Multiplier). Last time I tried the 12 Multiplier I could get into the BIOS but the machine wouldn't load Windows XP.
I changed the memory timings from 2-3-3-7 to 2-3-3-11 but haven't tried to get the 12 Multiplier yet. Dunno if that'll make the difference. With all the cooling measures I've taken you'd think I could easily get a higher clock but it hasn't happened yet
I've got a Lian Li PC65B and an Antec or Enermax PSU in mind for future upgrades... maybe that'll help to get it past the 11.5 barrier?