Yeah you will probably be OK. The 8800GT uses alot less power than the other 8800 cards.
But there is only one way to be sure. Do the book keeping and add up the power draw of everything in your case. You are listing only 3 components, but you have other things in use. Plus you want some extra margin, at least 20% over what you think the max draw is. And you have to account for anything you might want to add later or any OC you might want to do. It sucks when your PS causes problems, it is better to be safe.
It certainly depends on whose PS you use. A cheap PS's specs have to be taken with a grain of sale. The Corsair 550 mentioned above is super as is PC Power & Computing models. Try some PS reviews at jonnyguru.com
For the OP a quality 450w is plenty for a single video card setup. 8800GT cards use about 110w MAX under load so I don't think it will ever pull more than about 9-10a. The VX550 will give plenty of headroom if the OP is going to have LOTs of drives or an extreme OC on the quad. Even so, the 450 is plenty.