You know, looking back at movie lines over the past 10 or so years, it seems like the "successful" ones are few and far between. We keep seeing several each year, which is understandable, because when it comes down to it the lines with current movies or tv shows are really the ones that grab kids for the most part. Aside from Star Wars, there don't seem to be many that could be labelled as successful...
Lord of the Rings (at least while the movies were out)
Iron Man (first movie seemed to do very well here, although it was a more conservative approach)
Transformers (the first movie seemed to do better than the second)
Toy Story (that stuff seems to be doing well locally, at least the "normal" action figures)
Then you can look at the list that were either complete failures, or didn't do very well:
G.I. Joe - The Rise of Cobra
Batman Begins/Dark Knight
Fantastic Four/Rise of Silver Surfer
Pirates of the Caribbean
There are others that are borderline (for example, Spider-Man 2 seemed to do well enough here locally - although much still ended up on clearance), and each line probably has its fans (I mean we all liked the Indy line to some extent, but I don't think anyone outside of fans did). This doesn't even list all the animated movie lines, since I really don't follow those at all, but the majority of those don't seem to do all that well.
The one that always boggles my mind is Harry Potter. Here you have a movie series, much like the original trilogy, that has a broad fanbase appeal - but still has a focus on the younger generation. It has a potential long shelf-life with 8 movies when it is all said and done, not to mention the books themselves. It has a broad character base, as well as deluxe/beast potential, and even playsets (if they wanted to go that route). I didn't really follow the first couple Mattel lines, and there hasn't been much at mass retail since then. I think they had a fairly nice line in the U.K. recently, although I'm not sure if that is still going or not. Just seems like a lot of potential missed there.