N75 N80 or e61i
E61i seems to be these days one of the best devices to deal with RAM (the other is E90).
So, if battery life and RAM is very important for you, go for E61i. If is screen and FMRadio, then N80.
This isn't ENTIRELY related to your question, BUT I felt I should warn everyone... I recently purchased a Samsung BlackJack for it's features and Keyboard. Despite all the research I did, I am regretting moving away from the "Nokia" brand, because this phone SUCKS. Overall the phone isn't Entirely Horrible, BUT Window...
I waited a couple of months and got the 2nd one, unlocked and debranded it and now it's my absolute favorite Nokia of all. Symbian is great after a little learning curve - camera is really good - music & FM are really good - sound and RF are really good, etc., etc. On scale of 1 - 10 my opinion is 8.5 ->9.0 ... but there are many who disagree.
I paid full price with no contract and would definitely do it again.