I'd allow 90 minutes to get to downtown Dubai, but even with traffic, you have time to see a few things here. Personally, I think Abu Dhabi is prettier, actually. The corniche area is nicely developed and the water is really really pretty there. Plus you can see Emirates Palace, and then check out some of the malls.

ETA: Oh I just realized you meant Xmas 2007 not 2008. Sorry!!