I bought Apple's dual link adapter (http://store.apple.com/au/product/MB571Z/A/mini-displayport-...) . Was on special at a local store. It's not without problems, particularly awaking from sleep sometimes leading to "static" image blur requiring reconnection of the adapter.
When that happens, you can just put the display to sleep instead, then wake it a second later. That fixes the problem for me at least. The standard keyboard shortcut to put all displays to sleep is Shift-Control-Media Eject (⏏)
Odd, I bought the dual-link adapter from monoprice and I thought I got gypped when my wife's Yamakasi Catleap would wake from sleep that way. I guess mini-displayport is just flaky in general.