How important is the sit location?

for competition obedience - agility, therapy and/or frisbee are possibilities. And CGC is a big goal of mine. So how important is it that I work on getting a nice, clean, next to my leg sit? Or is this one of those cases where if I let her get sloppy here, she will start to get sloppy in other things?

 
I don't think it's that important if you're not going to do OB or rally and you don't mind.  (I've done agility, rally and therapy.)  Personally I _like_ a nice straight front sit and a nice straight heel sit, but I think as long as she is consistant and you know where she's going to sit when you ask her to, you'll be fine.

When anybody asks this question, my simple reply is:
 
The exercise is only as important as you want it to be.
 
I let my dog get away with a lot of things that hardcore obedience can't stand.  Like not having him look at me every second we're heeling.  I can't stand it.  I think it looks ugly and that the dog is behaving like a robot.  I've tightened up on this a little bit because of the schH work Mouse and I are doing now...but I still loathe that empty stare.
 
Debbie (one of my instructors) gets on me about letting my dog shift and fidget in the long sit and down.  I'm really relaxed about it.  I don't give a crap that he rolls on his hip or shifts on his feet as long as he isn't getting up or traveling.  Drives her nuts xD
 
If you want a nice straight sit, then be consistent and reward only for that.  If you don't care, reward for what you want.

I say as long as your dog is sitting when you ask it to sit, then it's really not that important where it sits. I feel the same way about asking my dogs to sit and they lay down.That's fine too as long as they are staying.Cute dog, by the way.

you realize dogs DON'T KNOW what is sloppy and what is not? they only know what they get rewarded for. If you don't care about it, your dog sure doesn't.

I agree, it's only as important as you want it to be. You can retrain if at somepoint you get to wanting to do performance that requires sitting a certain way. Marlowe generally only sits so he's facing me. That's how he learned the command and he never generalized to sitting in other positions. And I never cared enough to work on it and teach a neater sit. We don't do any kind of anything that requires formal obedience commands. And we passed our CGC handily.

For CGC, it doesn't matter where the dog sits. They just have to sit and stay sitting until released. The fact that your dog already has at least a sloppy sit-at-heel is way beyond what most dogs ever achieve, because for the vast majority of dogs which way they're facing when they sit is never important.