Uh... NitDroid is not full open source. It's the worst of two worlds. It has droid-based blobs, and sits on top of those and drivers hacked from Nokia-based blobs for the N900 specific hardware. Going to NitDroid, the only thing more "open" are the native apps and UI. The hardware level stuff is still just as closed.

That's not to say it's bad. I would love to see NitDroid running on the N900. I'd also love to see a VM or chroot level setup running under Maemo, so we could run Android apps on the N900, the way we can now run Pre apps via pre-env now. (I'd also like large sum of money so I could stop working for "the man" and devote more time to opensource projects, and a time machine so I could tell my past self to go to the gym earlier in life...)