How high should I let vcore go?

This is my first real OC. I've got the 1700+ paly in rig 2 of my sig. It is still locked, but I'm going to unlock it when my slk800 comes in. For now I have a generic cooler, so I'll really watch the temps.
I took it up to 150 FSB first off, and it ran prime stable for about 15 mins, so I decided to bump it up to 155. It would post but not load windows..I upped vcore to 1.775 and it would post and get to the choose user screen of windows and then restart again. I then took it to 1.8 vcore and it will load windows and run minor stuff like explorer or mbm5 but prime restarted it after a few minutes.
I'd like to keep going with fsb, and know I need to watch temps(which I will), but I'm not sure how high is too high to take a cpu like this(or any cpu for that matter) and would like to know what you guys think.
Thanks!!!!!!!

coz its a pally i would take it to 1.95Vcore with good aircooling or water but t-bred B's id only put 1.9V threw them

I wouldnt take it much above 1.85v unless it was showing a marked improvement. ie I wouldnt push it from 1.85 to 1.95v just for 50MHz. For 100Mhz or so maybe.

well i got to agree with david on that one i forgot to mention that