I thought it was supposed to be a 3.3v rail, not 3v. 2.95 would be pretty darn low for a 3.3v line... That's around 10% low.
I've read that the mobo sensors can't be trusted completely, and your best bet at getting accurate voltage readings is to take them directly from either a psu lead or from certain traces on the motherboard using a quality voltmeter.
I think some high end enthusiast power supplies even have built in voltage sensors and readouts so you can individually tune each voltage rail, but that's way too geeky for me. I know some memory modules now have LED displays attached to them that will read out temperatures, latency settings, and voltage, but that's pretty expensive. Some overclockers will find the right traces and components on their motherboards and solder on leads that they attach to a voltmeter and patch panel so they can monitor actual voltage to various components as they mess with their systems.
Again, that's too geeky for most people, so I think most people end up just buying a huge PSU and being done with it. PC Power and Cooling has a good rep and I think they sell a 550 watt or 600 watt PSU that should be bulletproof.
