i would say hold on to it for a couple years with a sale page at the domain. i have sold less admirable 4 letter dot coms for up to $250, just because the person wanted it so bad. you never know what might come along. IMHO ppl will gravitate to 4 letter dot coms for site names because 3 letters are too expensive, but 4 letters can still be easy to remember and market if done right.