+1 On Pictures. Pretty ridiculous to demand a valuation NOW as people are clambering to buy, but then not having the courtesy to post a pic (or two or three). Also I would recommend posters use a hosting site like Flickr (which is free) so that the pictures can show some detail.
It also would be good for responders to provide "full market prices" rather than super deals. While I could respond to many postings with a comment like: "I bought one just like it at a thrift store last year for $10", that is not what the bike is worth (at least in my opinion). I consider the value to be full market price, what someone should be able to sell the bike for locally, assuming they do a good job of marketing the bike (good pictures, good ad, that kind of thing). So my $10 find might be worth $5, or it might be worth $300.