Personally i'd wait till the new series of ATI/Nvidia cards come out. They're expected to be out within the next month or two.
Even if they aren't worth the price, the older stuff will become more affordable.
That's the advice I'd give, though if he has to have a card now, he might want to look at ASUS' overclocked 3850x2:http://www.legionhardware.com/document.php?id=746&p=0
It's neck and neck with the 9800gtx.
I'm quite sure the performance of the 4850 with GDDR3 due out mid June will be similar, without issues in games that do not support Crossfire. So, that would be the reason to wait.
At any rate, I wouldn't recommend two 3850's or 3870's right now, as just getting one and then going CrossfireX later with a dual GPU card is a better solution. For anyone with a single PCIe x16 board, I'd definitely recommend waiting for the 4xxx series.