The funny thing is, if we sign Lester, then I would not mind and might actually like if we did give up Owens for Hamels. If we don't get Lester, then I don't want to give into that loser, Amaro Jr. If we do surprise and get Lester though, then I sort of have the mentality of "Oh damn, we're really going for it this offseason!! Get them both!!" Not sure if that is a bad frame of mind to have. This offseason has been really exciting.
If we don't get Lester, then I'd prefer we do something like Latos and Shields as the 1 and 2, rather than give up our blue chip pitching prospect. We wouldn't have an ace, but we'd have two good #2 starting pitchers. I could see that team sneaking into the playoffs still, and then anything can happen with this lineup.
Goes without saying though, Lester is the #1 priority now.