I have a Asus P4GE-MX motherboard, but I only have a crappy 1.8ghz celeron in it, I am going to upgrade it either to an: Intel Celeron D-335 2.80Ghz or a Pentium 4 Northwood 2.6ghz
I'd go with the Northwood, though, frankly, if I were going to spend that much, I'd spend a little bit more money and get maybe an 805 and a new motherboard. Some 775 mobos will accept old DDR memory, so you can upgrade for about $130. Just something to think about. Otherwise, you can get slightly faster Celeron-Ds for like $30 now.