we just went through something like this
having just gone through a true bike theft situation you won't get too far without a serial number at the minimum, preferably a receipt from when you purchased, a polices report for the theft and photos would be the icing on the cake.
What if it DOES turn up on CL or a local pawn shop? Unless you have some form of proof of ownership, it's strictly your word against theirs.
A bike just like my son's turned up on CL just a few days ago. We got kind of screwed because we had lost the original sale receipt and didn't' have the serial number to put on the police report. LBS provided us with what we thought was a correct number that went on the report. I did find the original sales receipt about four days ago, and the two serial numbers don't jive. The chances that our bike got sold at a pawn shop becuase we had a serial number snafu are very high. I did get the police report updated. Anyway, it turns out the bike in question was exactly the same, a stock Haro but the numbers didn't match.