In my opinion, there's a lot of "you get what you pay for" in the PC power supply market. Personally, I'm a fairly heavy PC user, and, as such, I tend to go for as high a quality on such things as I can afford. Overall, it makes more sense to buy 1 good PSU and not have to worry about it than to buy 3 or 4 'cheapie" PSU's and have to replace it every 4-6 months.
That being said.. I am a *huge* fan of PSU's from PC Power and Cooling. Quality is second to none, and I've had nary a hiccup these last 8 months with mine, despite running 100% cpu usage for the last 6, lots of heavy AV apps, and several power outages.
For the 450W range, I'd recommend their ultra-quiet "Silencer 470 ATX" model.. it's got a 520W peak, runs very quiet, and their overall quality should ensure that it keeps kicking for a long, long time. It ain't the cheapest.. will set you back a hundred bucks plus shipping, but you don't get any better quality for the cash.
PC Power & Cooling is definitely good but for PSUs that won't burn a hole in ur pocket or ur PC, try ones from Antec, Enermax, Thermaltake, Fortron FSP and CoolerMaster. All these brands have high-quality PSUs with very good voltage protection.
Consider this one: http://www.newegg.com/Product/Product.asp?Item=N82E16817153023
Its a bit lower than the wattage you were looking for, but it is from a reputable manufacturer at a very good price, it's a very popular low-watt PSU (800+ reviews, wow).
Should be decent as long as you're not an extreme PC user - it does not have dual +12V.