Seating charts?

I'm getting some new furniture for my classroom this year - something like these trapezoidal desks on wheels, plus some rectangular stand-up desks.  My thought was to give the students choice in where they park each day.

1. I want to encourage them to work with different people. And we all know that once a student sits somewhere they're not too excited to move around - we're all creatures of habit! So how do you force/encourage that when you're trying to keep seats flexible?

2. For the past several years I've used table folders (ala Sam Shah) to pass out and collect papers. If I kept seats fluid, this wouldn't be possible. And this has been a lifesaver for me in keeping track of papers. But if I'm not collecting as much this year, is that as important? Maybe I just have stuff sitting by the door for kids to grab as they walk in?  (Sorry, just thinking to myself...)

What about using (I was just playing with it) to create groups of students and let them pick where they want to sit?  That would kind of incorporate both thoughts - flexible but somewhat predetermined.

My classroom has had some nice work done to it this summer and I'm excited to get in and get it set up. Looks like it's just missing the new "technology"; aka two ceiling-mounted projectors that will be facing the two whiteboards (currently blue) that you see in the picture. A third whiteboard is on the wall to the right while the fourth wall is a bank of windows. It has lots of nice natural light! (I just hope I have more outlets than the one I currently see!!!)