Crowning Music of Awesome: While some of the songs The Chipmunks cover are really good, nothing beats the great soundtrack of The Chipmunk Adventure. It helps greatly that most of the music is original work for once.
The songs from Alvin and the Chipmunks Meet the Wolfman and the opening number for Alvin and the Chipmunks Meet Frankenstein.
Face of the Band: Subverted. While Alvin gets a lot of attention, is the lead vocals on almost every song they have, is the star of the show, and was #44 on TV Guide's list of top 50 best cartoon characters of all time, Simon and Theodore are anything but forgotten or put in the background. Each of them have their special and memorable moments in the spotlight, each have their own fanbases, and all three of them share balanced screen time. Change anything, and it would not be the same.
Fan Nickname: The term "to chipmunk a song" means to edit the song to give the vocals (and consequently the rest of the song) a higher pitch. The term finds its roots in these characters. Just add "chipmunk" to any search for a song on YouTube, and you're bound to find one.
Oh, and watch out for fake chipmunked songs. "Real" chipmunked songs are actually pitch-adjusted (like real Chipmunks songs) and are the same length as the original. The fakes are the result of simply speeding up the original and are much shorter. Some people think that the former sounds better than the latter.
Girls Need Role Models. Initially the Chipettes were designed so the creators could make chick versions of songs sung by women, however the girls also ended up being main stars of the show and animated movie.
The 1987 movie ended up featuring the girls in such a big role, you realize they drive the plot more than the boys. The girls are shown in more locations, one song featuring both groups is called "The Girls of Rock and Roll", when they're captured they escape on their own, rescue a baby penguin and take him home, discover the diamond smuggling plot on their own and rescue the boys from their own capture just before they were about to be eaten by crocs.
Not to mention that the last episode Ruby-Spears produced featured no token appearance from either Dave or the Chipmunks in both shorts -- it was all Chipettes.
Moe: Eleanor might qualify. It helps that she's Theodore's counterpart.
Moral Event Horizon: Mrs. Grudge gets one in the Chipettes backstory: Binding, gagging, and locking the Chipettes away so Olivia wouldn't take them away with her new parents and she'd be able to make money off the three girls. They managed to escape, though.
Puppy Love: The Chipmunks and The Chipettes, who are all about 8-9 years old (though you wouldn't normally tell with the way they act).
Jerkass Has a Point: In The Squeakquel when Ian calls the principal out for being biased in favor of the Chipmunks and not allowing a democratic vote.
Moral Event Horizon: Ian crosses it when he threatens to barbecue the Chipettes if they don't do what he says. After doing this, it's almost difficult to accept the Enemy Mine situation with him in the next movie.
Ruined FOREVER / Tainted by the Preview:. Some fans who grew up on the 80's cartoon did not gravitate towards the eponymous Chipmunks looking more chipmunk than humanoid, and fans in general were not amused by the poop-eating gag shown in the trailer. Much to the latter's relief, the movie only really had two instances of toilet-humor.
Sequelitis: Mostly averted with The Squeakquel but may or may not have happened with Chipwrecked, which recieved mostly negative reviews and even David Cross went on the record of saying that just the making of the movie was the most unpleasent experience he'd ever had.
Squick: In the second movie, Alvin flirts with some human girls. High school girls. Think about it, then take a long shower.
Simon eating poop.
At least he didn't swallow it. Double squick.
The Chipettes having more feminine bodies in the movies. In the show they were in Elementary School!