I think it fundamentally comes down to what Rob mentions: Do the Reds want to win this year or 2009? If they want to win this year, there's no reason as to why Bruce shouldn't be the everyday CF (Veteran presence and Dusty's favorites aside).
I'm definitely in favor of the kid cutting his teeth up here from the first pitch rather than "seasoning" in Louisville. I'm excited to see Bruce get the opportunity to play every day, whereas I'm markedly less excited for the potential Freel / Hopper show manning CF (Do we need a Hoppinger-esque mash up name for them? Fropper? Hopeel? Heel?).
A final thing I'm glad Neyer mentioned is the reason why I let Norris Hopper pick my lottery numbers each week: "Norris Hopper's a born fifth outfielder who got incredibly lucky in the second half last season."
Yes, I only let 5th outfielders pick my numbers for me.