As for the built-in phone concept.
Sure - If somebody sees my n810 /and previously 770/ and is able to read "nokia" on it - it means "this is a phone".
In fact in Poland we don't have really cheap data transfer rates - every with some kind of GB limit.
If we could back in time let's say - 5 years it would be nice to have such transfers for this amount of cash but - the time passes by.
Everyone (well - almost) is getting used to min. 1-2-10MBit connection (and I don't think about cellular "super-duper" transfers promissed by HSDPA) at home.
Then - I should pay twice - once for home access, then for my pocket-access.
Since I've got internet at home, at work and at school - this would be a kind of waste for me.
Last time I was on bussines trip I had to use my E51 /connected to edge since there was no hsdpa at this spot/ for simple tasks like e-mail and www.
It was surely pain...
Why?
On mobile phone's when one uses something like "opera mini" where pages are optimized and are very small - downloading page in oryginal form (usually over 300 elements per page) takes so much time that I see it as unusable.
Today's webpages are killers for small computers - so what they do for mobile devices?
In this world - from my point of view tablets are VERY efficient in browsing as mobile devices. And everything slower than WiFi is only acceptable in critical situations.
Data lags between packets in cellular networks are so huge, that downloading standard web-page is highly inefficient.
Ok - I haven't seen iPhone3G in action but network transfer issues remain the same regardless of platform.
From that point of view - built in phone would be only a gadget for me.
I don't like the idea of such big phone but also I can't imagine using so small phone displays for the web (maybe I'm just getting older since years ago I was excited to have flat WAP rate with B/W display phone SiemensME45 then Nokia3650 and wasted a LOT of time browsing the web on them .