Well, I plan to keep my N900 as my main phone for quite some time, until I see the outcome of this. How Nokia handle Maemo/MeeGo after this remains to be seen.
A lot of Maemo developers are hoping they open source "everything", but bearing in mind it's still Nokia's property and doing so would jeopardize Nokia's copyright cases with Apple, so.... errrrm, it's just a wait and see game.
I'd love them to open up "everything" on the N900, then our restrictions would just be the hardware limits.

If I don't fancy another Nokia with WP7, then I may look towards the HP/WebOs market, see how that fares up.

Whatever happens, I'd still like to see the community keep banging away at our N900s. There's so much half finished stuff in the repos at the moment. Canola, Enna, Instinctiv were making out to be some good media players with nice front ends and features. Where the hell are the updates? Instinctive, we know about (thanks a bunch Nokia).

I'd like to keep my N900 for at least another 12 months at least to see if anything does appear on the MeeGo front. Who knows, Intel may find a new home for it if Nokia drop it.