Thanks in part to laptop stands like this two-tiered one by Staton, the days of lugging around crates of vinyl are slowly fading as DJs trade their decks in for laptop setups. Although we're the first to argue that nothing quite compares to a record, advancements in programs like Serato and the ease of carrying thousands of mp3 tracks have made going digital more palatable to audiophiles.
The Uberstand solves the issue of what to do with your laptop when you get there. After several precarious situations, I upgraded to Staton's Uberstand Laptop Stand. Unlike most stands on the market, it's made of aircraft grade lightweight aluminum and quickly folds flat into a 12" zippered bag. An included shelf makes a good spot for amps or external hard-drives, minimizing the entire footprint of the setup and allowing for cramming into small spaces. While it suffers a bit from stability issues, it is by far the best option we've seen for the traveling DJ.
The Stanton UberStand Laptop Stand is available for $80 from the Guitar Center.