From what I have played of the Harry Potter lego game It's enjoyable and fun. As for the Lego batman game. I have the second one and I like it a lot and from what I've read it's the one to get if your only going to get one lego batman game.
Star Wars: The Complete Saga is justly celebrated as the best of the LEGO games. I think I saw it on an all-time best PC games list.
Indiana Jones 2 is generally regarded as the weakest of the series. If you didn't like Indiana Jones 1, you'll want to skip this one. Others might fight it enjoyable to play, but you'd want to keep the purchase price under $5.
I would add Star Wars 3/Clone Wars to the list of weak entries. If you don't follow the cable cartoon series, the plot is incomprehensible. Objectives are poorly defined and have unintuitive solutions. All while scores of enemies attack.
The Harry Potters and Pirates of the Caribbean depend heavily on appreciation of the source material. If you don't like/haven't seen the movies, you probably won't like the games. In the Potters, players spend a good amount of time following a ghost around to reach the next task. By the midpoint of Years 5-7, we were fairly bored with it.
Batman 1 is lots of fun. It's older, so there's no dynamic splitscreen or dialogue. But the developers' not having to follow someone else's storyline is a real strength here.
Batman 2 is a bit short, but at Amazon's prices, that's nct really an issue. I found the city difficult to navigate, especially with vehicles, which are themselves difficult to control. The constant darkness and rain are a bit overwrought. The plot and dialogue are top shelf though.
Thanks for the info, I'll probably just pick up Batman 1 since I'm not too big a fan of Harry Potter (and I doubt casting spells would be nearly as fun as endlessly swinging away with a lightsaber), and LB2 has voice acting? Come on, part of the charm of the lego games is the comedic value from voiceless lego people.