It's great to get an answer rather than a lecture on how to use the search function.
Yep, it is. The search function sucks. It is hard to find specific questions and you end up browsing pages and pages of threads just to find something very specific.
SDHC sizes: I think the limit is 16 gigs now, but my impression is that the sky is the limit, or more likely, your budget.
I don't think you really need more than at most two 4-gig sdhc cards, do you? SDHC cards can be damaged, and replacing them can be expensive. As in gambling, don't bet what you can't afford to lose. I went for a long time on 2 gigs total, and it was plenty for me. Now I'm up to 6 gigs total.
Well, I'm debating between an n800 and an ipod touch. One of the big draws of the n800 is the ability to get as much or more memory than a Touch should I so choose in the future. I sincerely doubt I'd start with more than 8GB with memory, but I might very well upgrade in the future.