tiki room is worth it. not only is it a classic..but just the environment makes you (or at least me) just relax and tropical at the same time. plus the songs are catchy that you just start singing right along from start to finish.
"Your dead if you aim only for kids. Adults are only kids grown up, anyway." Walt Disney
Main St. Cinema is a good one to see since it shows where it all began. I hope Disney never replaces it with a store like they did at WDW.
Animation building at DCA is one of the highlights of the park.
Tiki is a sweet classic with a fun courtyard pre-show as well. Get a Dole whip while you're waiting there.
The only one you can really miss is Innoventions, which is a pain to finally get into to explore, and then after you do there's not that much to see.
I'd be hard pressed to recommend against ANY Disneyland or DCA attraction ... they all have their merits and are interesting ... but it depends how much a nerd/Disney geek you are! It also depends on how much time you have.
A lot of people have dissed in Innoventions ... and while it is clearly not of the park's stellar attractions, I like to duck in because I love that building! It's a fun thing to see if you've not been to it ... it's cool to check out once. But if you're tight for time and it's that or Star Tours ... yeah.