Nothing like my N900's Fn key to make me miss my G1 and it grand 5 row QWERTY. I'd rather have the chin.
Its the same with almost every other phone (bar perhaps the Touch Pro 2), and even the touchscreen keyboards. Drives me up the wall - ever since the Sony NZ90 which was a flawless organiser apart from the lack of the fifth row. I've never fully understood this. Yes, I know there are spacing and consequent engineering challenges on a keyboarded phone, but it strikes me as laughable when you're hearing stuff like 'x is coming out with a keyboarded phone for pro users'... who will in fact need number keys.
Seconding the 5th row on the G1. I will most likely be legitimately sad to see it go when I get around to upgrading.