Last time I was involved in in-person interviewing, we told people to bring a laptop with whatever software they were most comfortable using for development. Or

Last time I was involved in in-person interviewing, we told people to bring a laptop with whatever software they were most comfortable using for development. Or, we could provide a freshly-formatted Windows XP system they could install things on if they didn't have something they could bring. Worked out pretty nicely, and definitely made people more comfortable.