Pujols and Braun for sure. I think Tex and Hamilton are pretty equal. I might give Tex a slight edge since he's a Yankee. But I don't like to use up my utility spot (If you have one ) so early, so I would probably keep Hamilton. Maybe you could try and trade Tex to see if you could get a player that you would like more than Hamilton. M-Cab comes to mind . He can still play 3B this coming year.
Pujols is the must-have. You should keep Tex now that his runs total will likely take a big boost. It's a toss-up between Braun and Hamilton, but I like Braun slightly more in a keeper.
Pujols, Braun, and Tex if you want the best three. Sub Rollins for Tex if you want the most well rounded team going into your draft. Please take a look at mine.