Ellsbury, to me, looks like he can be a very talented MLB player. If you didn't notice the holes in his swing, and his tendency to swing at crap in the dirt, you need to open your eyes.
Ellsbury's BABIP was .380. My eyes felt as though he got a few cheap hits along the way (a few - a lot).
You've loved Ellsbury for a while, so I bet it's probably not going to matter what I say here. But to just hand the reins over to Ellsbury right off the bat, especially with how well Crisp played defensively (OVER 8 WIN SHARES).
Do I think Ellsbury will be the better player? Probably. I'd really like to see the team hang on to both players for '08, and transition Jacoby into the CF job after a month or two.