Let the hive mind of Engadget get that for you.
"I just switched to Sprint from Verizon about three months ago for the Pre. Then I went for the Hero about a week ago. Now, I miss my hardware keyboard and am thinking about switching to the Moment. I am still able to switch back to Verizon if I want and get the Droid when it arrives. Should I just trade up to the Moment when it comes out, see if I like it, and if not switch to the Droid? Or something else entirely? Help!"
I don't think they have a problem making 'skinny' S60 phones (E51 is plenty thin packing in wifi as well), I think it's more that Nokia still doesn't seem to 'get' flip phones.
If anybody have been reading my earlier post you know i'm a Nokia fan, but i couldnt ever recommend Nokia flip to anyone. I have personally had so horrible experiences with Nokia's flips all them have had major problems(dont even talk about 6260 or N76) compared to Nokia's bar and slider phones that have been problem free.
Nokia is the bar phone king by big margin and is able to make good sliders(8xxx and E65)thought with sliders it's a bit more of some models are good and some not that good.
Nokia can make thin smartphones as E51 shows and so will coming E66 and E71. It's just that most of the new models are packing at least 3mpx cameras, but Nokia should make thin low N series phone like N7x.