Denmark and I started watching 30 Rock, and it brought back some warm feelings how AWESOME Jack and Liz are together I also totally love that they only ever stayed awesome bro BFFs and never got romantically involved. It really is a refreshing dynamic in a comedy between a man and woman.
The Tenth Doctor and Donna also come to mind as two awesome best friends who just enjoy hanging out because they're friends. They have such a deep and resounding love for one another, but it's not romantic love.
Marshall and Ted from How I Met Your Mother. They're both serious (enough) and intelligent guys, but they act like little kids and do the dumbest stuff together.
Patsy and Eddie from Absolutely Fabulous. Two alcoholic drug addicts who are sex-crazed and reliving the 60s even well into the 90s and 2000s. The only relationship they can make work is the one they have with each other and it's so smurfed up and hilarious and beautiful.
Kirk, Spock, and Bones and a trio. Spock is the brains, Bones is the Brawn, and Kirk is the Beauty. They all nag and pick and smurf with one another and they're just perfect in every damn way.
Lorelai and Rory from Gilmore Girls. Okay, yeah, they're mom and daughter. But they're also best friends and understand each other in and out and I dunno. They are the epitome of both a perfect friendship and perfect mother-daughter relationship.