To tell you the truth, judging from the trailers I've seen, I'm not sure that the on-screen Joker looks that much like Ledger to me. In any case, I don't see any more of Ledger in any of the other sculpts, so I figured I would go with the Hot Toys version for the superior accessories, and to have the "complete set" of HT stuff when I get Batman and the Batmobile.
By the way, I remembered that Microsoft is doing their Live.com 20% discount for ebay buy-it-now auctions, so I got the figure from an ebay seller. With the discount, it came to $147.65 shipped, and that's with EMS shipping. Not too bad, I guess.