I'd played some of the Lego games almost a decade ago with my nephew, and even at that time I didn't find much to really interest me. I thought I should give them a closer look, though, so I started with Lego Star Wars: The Complete Saga on Wii. This is actually a compilation of the first two Lego video games, Lego Star Wars: The Video Game, which covers episodes I through III, and Lego Star Wars II: The Original Trilogy, which covers episodes IV through VI. The Wikipedia entry on the Wii game has a lot of info on what that version adds compared to the originals.
I'm not a fan of the Star Wars movies by any stretch, but I remember enough of episode I and I had rewatched episode IV not too long ago, so I focused my time on those parts of the game. The gameplay is very simple and family friendly: you're mostly just wandering around 3D stages doing some simple platforming and combat and some simple push blocks/stand on switches types of puzzles. There's drop in and out co-op and there are no game overs; if you lose a life you're only penalized by losing studs, the game's currency that is mostly used for unlocking extra characters, etc.
The game has a ton of characters, most of whom are pretty useless. The characters fall into distinct groups based on their abilities. For example, Jedis can use "The Force" to move things around, whereas some characters can jump higher or use grappling hooks. Characters of the same type are completely interchangeable, so in free play mode (available for any level you've beaten in story mode) once you've unlocked at least one of each type, using another of the same type is purely based on your aesthetic preference. The game switches things up with some vehicles or animals you can hop into or onto, and there are also some vehicle-only segments.
It's easy to breeze through the episodes pretty quickly, but going back to find all the collectibles (ten in each stage) would definitely take some time. Each stage also has a "challenge" mode where you're given a time limit to track down ten other collectibles to complete the stage. The game is pretty mindless, and tracking down all the collectibles seems more a matter of time rather than effort. The graphics look pretty mediocre even for a Gamecube ported to Wii game, and although I'm sure Star Wars fans love the soundtrack, I found it to be pretty forgettable. Also, the series has been lauded for its sense of humor. The game features wordless cutscenes, but I found the humor to be the most basic type of slapstick that only young kids would really love, e.g. someone falling on a banana peel, or whatever the Star Wars equivalent would be.
Well, I guess that's about it for Lego Star Wars. It's a decent game for kids, but otherwise doesn't do anything particularly well (or particularly badly). It seems the developers have been churning out Lego video games at a steady pace, but from what I've seen the series has been very slow to evolve. Being a Marvel fan I'll probably check out Lego: Marvel Super Heroes, and Lego City: Undercover got good reviews so I'll be checking that out as well... eventually!