I'll echo a700's post about not changing the 3/4/5. That being the case, two of Ellsbury/Pedroia/Crawford can fill the 1/2 spots. Whoever it is doesn't matter to me. I think it's prudent to stick with Ellsbury/Pedroia because despite Crawford's recent surge, he's not hitting better than JE since he took the leadoff spot, and Pedroia is RH, an excellent #2 hitter with speed on in front of him, and a good bet to put up better offensive numbers by season's end. I don't disagree that when he's going good that Crawford is a top of the order hitter, but so are the other two, and his talents don't warrant moving Gonzalez/Youk/Ortiz down in the order. It's is simple as that.
On another note, how nice is it to have this discussion? With Lowrie hitting the way he has, the catchers getting the memo and pulling out of their funk, and Drew still being a grinder who gets on base, this lineup is loaded. So what if Crawford hits 6th, there are worse problems to have. Enjoy it.