Audiogon has improved the site significantly just since I started coming here, about 2 years ago (to browse and buy - I only started posting later). The site still has a few minor quirks and a couple of functions that could be added or made better, but overall I'm extremely comfortable using it (I sometimes suspect too much for my own good!). And of course lots of helpful, worthwhile members - that's what makes a web community, so give yourselves a pat on the back.
Here's a couple of features I would like to see: 1) The ability to re-post a running classified ad back on the New Today page at any time for the usual charge; 2) A feedback system that calculates total ratings by unique posters only, instead of a simple aggregate - especially since, unlike a primarily auction-based, transactor-mediated site like ebay, the classified transactions that make up the bulk of A'gon trading are not verifiable, and anybody (even, in theory, somebody you haven't actually comsumated any business with) is free to access the feedback feature and post as many times as they like.
I would also like to see a catagory for Music Reviews!
A'gon's the best, and still my only - Hear Hear!