Ideas for this year and from the past
Probably not exactly what you're looking for, but I'll throw it out there just for the record: Seoul.
If I can get Mr. Megatop to sign off on it (I've already scored him a business class ticket BKK-ICN, what more can I do?), I'm going to do a DL mileage run of sorts to Seoul for Labor Day weekend. Take just two vacation days, get nearly four full days in Seoul. I'm told September is among the best times of year to visit Korea.
I did LA last year and it was fun enough: good weather and all that, plus a party at the Mayan Theater. SF last year had a Fresh event at Ruby Skye on the Sunday of Labor Day, which was reportedly a blast, and that's an ideal time of year for SF, just on the cusp of harvest season for wine. In 2003, I did New York, which was a lot of fun. In 2002, I did Toronto, which was fun but that probably wasn't the best weekend to visit, as a lot of folks seemed to have gone to Montreal. (Canada celebrates Labor Day the same day we do, so it's a long weekend for them too.)