I still think that Walking Dead hasn't been able to re-create its pilot on a quality level. If there's one thing to learn about 28 days later and Walking dead, guys waking up in hospital during a zombie apocalypse always makes a good introduction to the story.
Without quoting the other guys, Community had a great pilot. I'm hoping the return of Dan Harmon will bring back the wits and charm the show lost during season 4.
I liked the pilot for the spin-off series of Angel. It's not flashy, but it gets the job done to introduce a good series.