I looked at the new CX power supplies, and it does seem like they are a lot more reliable if they have a five year warranty instead of the previous 3 year warranty. However, I think 450w is still too low. 550w would provide more room for upgrades, and probably better efficiency as well. It also might be worth getting a TX power supply instead, as they are not much more expensive, but they have gold efficiency and a 7-year warranty.