400-500W PSU as/for backup

Right now my backup PSU is a MIOS 500W, used for about 2 years, and it's at least 4 years old and very cheap and basic, and super loud.

Whats a cheap 400-500W PSU I could get that I could trust a 6950/7950 with, because that's not it. And ignore my sig rig for this, since I have a 65W celeron G540 in a H61M-P31 microATX backup rig too, so I would consider 400W too, or 500W for my main rig.

I won't be doing this for at least a month so ignore deals

There a some very cheap $25-$50 coolermasters and thermaltakes, and others here
http://www.directcanada.com/category/?minorcatid=1308&pricerangeid=1002

any thoughts, warnings, etc

The Thermaltake TR2 series is terrible, as are most (all?) cheap Cooler Master units. In both cases they're very old designs of dubious quality
Same (at best...) goes for Raidmax, Apevia, Logisys, and pretty much any company that makes a unit with an MSRP in the 30s or less.
(As a sidenote: both CoolerMaster and ThermalTake make some excellent PSUs, but they're higher end units and significantly more expensive. Raidmax/apevia/logisys are universally junk)

On the plus side, that site has the go-to unit of choice for low cost won't-explode performance: http://www.directcanada.com/products/?sku=11180AC2578&vpn=CP-9020046-US&manufacture=CORSAIR
I would go for that, or for one of these two off newegg.ca:
http://www.newegg.ca/Product/Product.aspx?Item=N82E16817151077
http://www.newegg.ca/Product/Product.aspx?Item=N82E16817371033

Alternatively it might be worth getting classifieds access here (you have enough posts, just need an ISP or .mil (or .edu?) email address) and checking with OW to see if he has any low cost units for sale. He's in canada, so shipping is a lot less from him than from us down in the US.

yeah I read some reviews of the ones there last night, the only one that seems alright is the cosair CX430W, going by the review of the CX400W which is made by seasonic for cosair
http://hardocp.com/article/2009/02/16/entry_level_power_supply_roundup/7

I might just cough up the extra $15-20 and look some around $50-65, there are some there that look more promising

the thermaltake TR2 500W is really only a 375W according to this and how bad it fails on the 12V line
http://www.hardwaresecrets.com/article/Thermaltake-Purepower-500-W-Power-Supply-Review/990/7

makes me wonder how bad the MIOS 500W really is, I've used it for a solid month with a 6950 last year when my M4A89gtd needed to be RMAed, but that was in a P4 so I couldn't play any modern games

actually the CX430W is not seasonic, it's CWT or something, but it's still a good egough build. I'll get it or the CX500W

The CX400 was a better PSU than the CX430 is, sadly.
The whole CX line is at least decent, which beats almost anything cheaper