Ooh thanks for all the replies everyone! So many good suggestions and for some new bikes that I wouldn't have thought of.

I had been considering the public bike, but my coworker just bought one, and the green is out of stock until the end of December, AND there's a waiting list.

I live in Portland, OR and I've checked out the resale market a bit, but it all seems a bit overpriced. I do love the idea of buy a vintage frame and fixing it up, but only if it's lightweight, so i'm not sure if thats possible?

Thanks again!