I think Hogwash covered your questions. If not, feel free to ask.

After all the discussion, i think what you are really saying is that the N900 isn't a Windows-compatible computer. There's no arguing with that. Any random piece of software that's popular on the desktop isn't likely to run on the N900, so a lot of what people are used to (e.g. MS Office) isn't going to be available. This is simply an issue of market support. It's a valid reason for not buying the device, and is the root of the strength of MS's position and the continued survival (and indeed flourishing) of an unquestionably inferior mobile OS like Windows Mobile 1-6.

There are some viable analogues to windows-specific software in linux land, but they do require a certain amount of time to learn, as with any new paradigm or program.

Correct. Even so, you can't install Windows IE on your WinMo device....even their own software requires porting to the new platform. At least Microsoft have both platforms fully under their control, however.