Blimps and zeppelins are slowly but surely making a comeback. While they may not be the best way to ferry people around the world like in my steampunk fantasies, the unmanned variety, such as Lockheed Martin's HALE-D, are ideal for taking the place of satellites.
The HALE-D is a high altitude long endurance demonstrator — thus the acronym. In other words, it's a big fat robot blimp that can float up really high and then not come down for a long time. It's designed to operate up around 60,000 feet, using a big solar array on its upper surface to power itself and its payload. The HALE-D floats up above the jet stream and then uses its motors to keep itself parked in one spot, offering a 600-mile field of view for short and long range missile warning, surveillance and target acquisition, communications, environmental monitoring, and whatever else you can come up with.
With the HALE-D, you basically get a platform that's similar to a satellite, except it's faster, easier, more versatile, and several orders of magnitude cheaper. Oh, and you can get all your fancy electronics back when you're done since it's significantly less likely that aliens will come by and steal your stuff.
It looks like Lockheed just finished up construction on the demonstrator, and we've got some pics of the rollout in the gallery below.