Named PSUs are much of a muchness these days (in terms of cost, reliability, stability etc). The major difference will probably come in warranty period. Corsair PSUs have a good reputation, I've got on of the HX series which are modular (so you only need to connect up as many cables as you need...you don't have 10 extra Molex connectors cluttering up your case). 'Named' ~500W PSUs will start around £35 and go up to about £55. You would probably be able to get by on a lot less than that unless you have crazy power needs like dual Graphics cards. On replacing the Antec one...how old is it? PSUs generally have quite a long life span of several years so unless it's 4-5 years old I wouldn't replace it at the moment. Of course, if the computer it's in starts having stability issues or randomly crashing for no apparent reason the PSU will be one of the likely suspects.