Noisy is relative, if you replace all your fans with noctuas, suspend your HD and put a Accelero S1 on your video card the 80mm fan in your PSU will become quite loud
The wattage of the Antec PSU is deceptive, because it's dual rail vs. Corsair's single rail. You won't generally be pulling a balanced load on the rails, so you will run into problems long before you hit the max wattage on the Antec (some of the higher end Corsair's are also multirail in name, but they simply couple the rails when you pull too much power from one). I'd bet that most of the time the VX450W can service heavier loaded systems than the Antec EA500.
For a couple tenners more you can get the Corsair VX550W.
That PSU can do loads of 500 watts easy. http://www.silentpcreview.com/article684-page4.html
It's a review of the 430 watt version, but there are no major differences between the 500 and 430 versions, AFAIK.
It's a very good PSU, and will give him plenty of headroom.