It's interesting to finally see what's going on in Mozilla Labs around Bespin. It's an interesting idea, making a web-based development environment. It's been tried before, but I'm curious to see it develop and see how far they can take it.
What they have already seems promising, but it's a long way from replacing a desktop application for me at this stage. Still, with enough persistence and enough time, there are undoubtedly some things a web-based application could do that would be difficult for a desktop application to mimic. We'll see what happens.
I'm not sure developers are ready to move their development environment into a browser. More specifically, I'm not sure that it will be possible to create a compelling, seamless enough web development environment. But if it can be done, these are some of the people I'd like to see working on it, so I'll keep my fingers crossed and keep my eye on Bespin as it evolves.