I also enjoyed Mike Judge's other film "Idiocracy". It's not explicitly a hacker film, but it's a sci-fi story about an average guy in a world of idiots, so it verges on hacker territory. It also has some examples of hilariously bad human/computer interface design.

(And if you're into cry-yourself-to-sleep-reality movies, there's also Outsourced, a recent comedy about a call center manager who must train his replacements in India. I found it surprisingly enjoyable. Its primary themes are culture clash and figuring out what's important in life, so it shares similarities with Office Space and Gung Ho.)