It's a crazy world! Thank god for ATI though since before the 4870/4850, the GTX260 was $450!
I would personally recommend one of the 4870s. You don't even need the XOC Diamond one because you can almost get those speeds with the ATI overdrive function in the CCC that comes with the card. Might as well buy one of those for $280 then get your $30 MIR.