what is your system? what hardware are you powering?? i would be tempted to go with the OCZ as they have taken over PC Power & Cooling (one of the best power supply manufactures in the world) but it would help if we knew what you want to power lol
you should be fine ifyou get any of those 3 you sujested. i would personaly go for the 600watt OCZ as i have seen some good reviews about that power supply being able to supply over 700watts in total and still keep all the voltages wel within spec. as far as i can see you should be fine with any of those 3..... so it comes down to personal preference price and upgradability (the 600watt giving you a tad more power if you decide to add more in the future)
where do you intend to buy from? from the prices i have been looking at there is no more than about £20 difference at most. personaly i would get the best i could and IMO thats the OCZ, there isnt much difference price wise. they are all good performers and all powerfull enough for your system so its up to you which make you prefer and if you can find any deals to sway the balance. hope this helps
I have the Coolermaster Real Power 550W SLI PSU which for some reason was discontinued but the 450 was kept. I can say that compared to my case fans it is silent, and the rails are constant.
But as this is discontinued you wont get it easily, but it does fit your criteria.
I would always suggest getting a PSU model that is recommended instead of just a brand, as some models for some reason can come out poor and it is best to find an individual model that is recommended. All of the brands you have listed are good, you just have to find a PSU in your range that has generally good reviews and the Corsair seems to be coming up good.