[Fomalhaut]

First, I'll state that I haven't seen ALL of the episodes.
Second, I'll exclude the Pilot, though I'd put it at the top of the list nearly everywhere.
Third, I won't put my fave episode in other rankings, though it's my fave for many reasons.
Fourth, I may change my mind. It's pretty hard to choose.

Favourite: Duchess of Wails.
Least favourite: Ummm... Blooo or Phone Home, I guess. Blooo because it made me LMAO the first time, but the second I was just bored. And Phone home was pretty silly, though I liked the Wilt part.
Most boring: Phone Home.
Funniest: Camnp Keep a Good Mac Down/Gags in Bus The Two of Us.
Least Funniest: Phone Home, still.
Best Character-Based: Seeing Red/Cuckoo fo Coco Cards/Go Goo Go/Berry Scary.
Worst Character-Based: Mac Daddy/Where There's a Wilt There's A Way.
Best Written: Who Let The Dogs In?/World Wide Wabbit/The Big Picture.
Worst Written: Hiccy Burp. Half of the episode passed with Bloo having hiccups and Blake Superior burping.
Tearjerker: Go Goo Go, the end.
Most annoying: Bloo screaming in CCC... ow!
Silliest quote: sorry, but "Hot in Topeka" annoyed the cra- out of me.
Best with most characters showing their particular traits: Infernal Slumber.
Best Duchess moment: "Frankie! Turn off the alarm clock/Open my eyes!"
Worst Bloo moment: I Only Have Surprise For You - listen, don't you think he's becoming too much of a jerk now? Poor Mac!