I'm running the AN7 motherboard and I find 2-2-2-11 to be the best timings. If your memory is more likely to be stable at 2.5 I would consider 2.5-3-3-11. I used Sandra's memory bandwith to test various configurations and ended up with 11 being the best for bandwidth. I drew this conclusion after reading about it from others with NForce based boards on the ABIT forum: ABIT USA Forum
If you scroll about halfway down there is a section for NForce 1&2 motherboard discussions. There is also an overclocking section clear at the bottom.
If you have the time and the patience I would consider downloading Sisoftware's Sandra and doing some memory benchmarks to see what works best for you. Hope this is helpful, good luck.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS