I would love to have Prince on this team either this year or next, but the thing is that Werth deal really screwed things up. He's probably now going to want/get a $130-140 MM contract now, and with the recent Dunn signing I don't think the Sox would be willing to commit that much money over that long of a term, even with Buehrle's contract coming off the books, especially considering the Sox needed Dunn and AJ to defer money from their 2011 salaries to clear space for Konerko under the budget. I love that JR has opened his pocketbook this off-season, but I really don't think he is in "blank check" mode, and that is certainly what would be needed to go after Prince via the trade-extension or free agent routes.
All that being said, Prince Fielder is one of the best in the game, and his OBP and power-hitting abilities would mesh really well with US Cellular Field. I'd want to talk to a doctor or two about his aging prospects given his physical stature, but he would be an absolutely amazing player to put alongside Adam Dunn.