Three full weeks have passed since the Burning Crusade was released, and I'm level 42. Simple math says that's approximately 2 levels a day. This number is largely misleading as the first twenty levels can be done in a few days, and it is the later levels that take days to finish. At this point however, I see very few Blood Elves at my level, because I'm ever so slightly ahead of the curve. At this moment in time, there are 200 Blood Elves logged on, and only 30 of them are above level 40 (of which two of them are mine). The majority of them are residing in the 21-40 level range, which has been great for me, as it means that junk equipment that is too low for me to use (and too good to disenchant) tends to fetch nice prices at the auction house (which definitely helps, as my characters are constantly broke)
I suspect the levels from here on out will be slow -- what drives me to race to level 40 are the mounts for characters and the ability of the mail wearing classes to be able to use plate mail. It's pretty sad, but some of the equipment I'm still using are quest rewards and blues from level 18-21 -- most of this was motivated by my desire to own a mount at 40, which necessitated saving up every last copper piece between the two characters. I still haven't updated my paladin to Plate Mail completely, and most of the quest rewards of plate has been great for Warriors, but not so hot for a Paladin.
Still, the reward is quite worth it, as the following screenshot shows in our patchwork low-level equipment glory: