Thank you all for your comments. I have to admit that three endorsements of the Shimano PD-M324s was not quite what I expected.

Nashbar has Shimano PD-M647s on sale for $80, so I ordered them from Performance (with a price match and a 20% coupon) which made them just a little more than half ($64) of MSRP ($115). I figure I can always return them (or sell them on eBay, for about what I paid), if they're worthless.

I'll report back with my opinion of them as soon as they arrive.