I'm not gonna criticize - seriously, this time. I'm just gonna say, the first image that came into my head was a Hollywood blockbuster blow'em up movie, probably because of that one trailer Sawako summarized in Episode 25 (I think?). lol Don't get me wrong, I'm not saying it's gonna be cheesy. It's just me daydreaming how cool it'd be (for me) if the script is written in like, a really epic sense. "K-On! The Movie! Hirasawa Yui! Akiyama Mio! After School Tea Time! BIG. BLOCK. LETTERS. Don't miss their finest performance! BOOM BOOM BAW!"
In all seriousness, I'm surprisingly expectant towards the coming of the movie. I've seen quite a few anime movies (though mostly just Detective Conan and Digimon movies) that really have something gratifying to reward you. Though this does not mean that the accompanying movies are better than the series (of course), you could usually find a really awesome factor in the movie the series normally doesn't have. Not like a filler, 'coz a filler just gets the plot moving. An anime movie, however, just feels... awesome.
Or perhaps it's just because I haven't the chance to watch an anime movie for a while.
"Wow. K-On's got a movie." Just listen to the sound of that, and smile. Heh.