Depends:

- on each new device I have a list of favourite apps, with N900 I took a leap of faith and I'm glad I did - for maemo6 I'll wait till their fully ported if such a thing will even be necessary.
- I didn't want a keyboard but now I don't know how I could live without it, so it depends, rumor has it maemo6 will be keyboard-free
- N900 was quite expensive when I got it, compared to now but... my ol' symbian was falling apart, so I'll get maemo6 @ min 3 months after the release.
- hardware: to be worth it I want to see improvements in video recording and certainly no downgrades. Don't care about multitouch.

So in the end it has to be a shock and a huge leap forward in technology, the way N95 and N900 were, to be worth it.

I really don't see a worthy rival for N900 yet.