I loved the Davy Back arc. Not as much as Thriller Bark, but it was still fairly amazing.
I think the Straw Hats are very much like characters in old '70s-era Hanna-Barbara cartoons – they're at their comedic best when roped into doing silly, pointless stuff for no reason whatsoever except to make Zoro and Sanji squabble, Luffy to do something stupid and reckless, Usopp and Chopper to get scared out of their wits, or just to give poor Nami another migraine.
And it's not just the goofballs like Luffy and Usopp either that make this stuff great; Robin reading the book while paddling the raft was awesome. Her potential as the crew's icy-mystery-woman straightman is sadly underexplored in One Piece. (Although after the emofest of the CP9 saga, Oda did well to kinda get her back to that old mode in Thriller Bark, with stuff like her conscientious objection to Tactics Fifteen).
Why does Davy back exist? Because it embodies what One Piece is really, truly all about -- a gleefully retarded rubber kid with a bunch of wacky friends fighting and/or befriending ludicrous cartoon animals, all while punching the shit out of some evil guy/girl who might actually be weirder than he is (does Kaidou have Moria's chin stuffed and mounted somewhere in his cabin? Forget the secrets of the Poneglyphs, THERE'S a real mystery...).
Also, Luffy vs. Foxy was an amazing fight. "HEY! ARE YOU HIS SISTER?!"