Just for comparison, my .67 Pearl is getting about the same 2days usage if lucky. I usually have Yahoo messenger running (but no activity) and get emails, but don't check it that often.
The only thing that may be an additional driver is that my signal strength at my house is marginal, and in the past that has meant my phones would be seeking signal sporadically. This of course drains power quite nicely. However I haven't noticed it yet w/ the Pearl, unless it's just not as quick to report a lost signal as the 8700 was; alternately maybe the reception is just better.
Either way, I too am disappointed w/ the battery life vs 8700 but I do like the little guy