My experience, after about a month of using the following setup, is that it replaces any need for pen and paper, at least for what I use it for. I do a lot of note taking in meetings, etc, and that often includes diagrams. My setup: Ipad2 Evernote Dropbox NoteShelf an Adonit Jot Pro Stylus. (This is as good as a balpoint pen on paper, with the right note taking app). I've also tried out UPad as a note taking app, it works quite well - I just preferred the look and feel of the writing in NoteShelf overall.

The Phoenix lander is going to the pole, so it isn't expected to survive long enough for dust on the panels to be a problem. The mision is 90 days. Once winter comes, the probe will be frozen in carbon dioxide ice, which will pretty much kill it. I believe they plan to try to talk to it again when summer comes the next martian year, just in case it survives though. The next Mars Rover, the MSL is planned for launch in September 09 and will be powered by a RTG (radioisotope thermoelectric generator). Same as what the Voyager probes used and they are still going 30 years later.