Honestly, I think Holliday is the safer, more consistent play. I don't foresee him missing time this year, and though he did last year, he posted very reasonable stats when he played. Not so sure how the Pujols loss will effect him, but Beltran isn't a slouch. His downside is his age (32 this season), coming off minor injury, and plays in the OF, which is more stacked than 3B.
Wright has more talent IMO. He just hasn't been the same guy 2 of the last 3 seasons. His power was sapped last year (probably due to injury) and in 2009 as well. But with the fences being moved in, I think he can post good power numbers again. His speed improved last year, and with injured guys and/or not so great guys in front or him or behind him, I'd imagine he gets to run a tad more frequently. I think that in 2012 he will produce a line close to that of 2006, but with less Runs and RBI. Similar HR, SB, AVG, and OBP.
I think I would go with Wright as of now.