I've played most of them apart from the Lord of the Rings one. I agree the Star Wars ones are brilliant. Especially if your are into Star Wars.
The Pirates of the Caribbean was also quite decent.
Most of them are extremely enjoyable. Probably my favourite gaming series taken as a whole. Such a brilliant concept and extremely well executed.
My issue with Avengers was the repetitive, flat levels. It's just like, do this thing. Ok, I did it. Next part.
Pirates of the Caribbean had some very clever puzzles, if easy (for the most part; some of them are like "OOOOHH that's how you do it; heh clever." and Lego Star Wars III has excellent, difficult but rewarding levels and gameplay. I also LOVED the crazy rooms and things that you could access when playing in free play. Star Wars III really perfected free play in lego games in my opinion.
I haven't finished Avengers, but none of the levels I have played have been particularily clever.
But worst of all, it's just a pain to play. The animations are TOO. LONG. In star wars III, double jumping and attacking with a light saber was always quick but just long enough to be satisfying. Doing hulks smash thing just takes way to long, and does hardly any damage. You feel like a bad ass doing that in Star Wars, and I was sure doing a hulk smash was going to be awesome. It isn't. It takes forever, and you're usually just much better off switching to another character to take on bad guys. Changing to Bruce Banner also takes WAY. TOO. LONG. I just want to play the game, damnit. Stop making me wait for your pretty-only-the-first-time-you-watch-them animations.
I hadn't really watched a whole lot of Star Wars before I played III. I only played it because it came free with my 360's 320 gig hard drive. And I had watched or even really hard about NONE of the Clone Wars stuff. But dang it Star Wars III is just so good.
I don't have one (yet).

I imagine (from what I'm reading in the other page) that the 3DS version is quite different, although I'm flirting with the thought considering its portability...
If all games are generally decent, I may just go with the franchise I feel more hype by March (when I plan to play one). I'm a fan of all the licences they've used, but I'm sorta between Indy and LotR right now. Thanks for your recommendations!
By the way, I imagine PS3 has crisper graphics, but as a fan of the Wii Remote / Nunchuck combo, I gotta ask; will I miss out on the visuals more than I will win in controls by choosing the Wii versions?
What all systems do you have, btw?
Lego Indy 1 is ok, but sort of boring. Not a bad game by any means like II, but just not as good as some of the others. It's not a bad intro game though. You can't go wrong playing it first; just don't get discouraged if it seems boring. I haven't played LoTR, but what I played didn't impress me as much as some of those before it; still pretty fun though, but like Avengers (though not as bad) it had issues with over long animations and cutscenes. The cutscenes are long because of dialogue. Previous games did an excellent job of communicating with short animations of miming and stuff. It was brilliant, funny, and shorter.
I really, REALLY recommend Pirates of the Caribbean and Star Wars III (the Clone Wars).