One is your wife/husband/spouse.
One is your best friend.
One is your co-worker.
One is your pet.

For a pet, please pick a non-humanoid champion (Champions with highly bestial traits like Ahri are okay.)

Validating your ideas makes it more fun!

Picking a specific skin for a champion is great (I.E. Corporate Mundo for a coworker)

I would marry Cassiopeia. That snake tail would be great for spooning. I mean, what?
Blitzcrank would be my best friend. Many laughs would be had rocket-grabbing cars off the street. Or maybe I'm just a sadist.
Caitlyn would be my co-worker. Even head, highly intelligent, awesome top hat.
And finally, my pet would be Kog'Maw. Do I really need to say why?

I would marry Le Blanc. Because why have 1 when i can have 2? And it wouldn't count as cheating!
My best friend would be Brolaf. I think i don't need to say why.
I pick Heirmendinger as co-worker. Smartest person on earth nuff´said.
And my pet would be Nami. I would have her swimming in my pool all day :3

I would marry Janna, because she's just so supportive.
My best friend would be Rammus because he is so gosh darn agreeable. All the time.
My co-worker would be Amumu, because I like to have a good amount of misery around me when I'm working. It makes me feel better.
My pet would be Teemo (he's actually a large squirrel, not a yordle) because I don't want a guard dog, but I do want some extra security around the house.

I would marry Kitty cat kat, do i need a reason?
My best friend would be Corki because i can use his Aircraft.
My pet would be Singed because i can make him poison who i hate.
My co-worker would be Sona because there would be no need for Med kits!
My pet would be Nasus because he could act like a statue and they'll never see it coming!

Ima add this in, if i could be any lol champion i would be rammus because i can put you see me rolling music on!

I would marry Shyvana. Because dragons.
My best friend would be Twisted Fate. So many cardgames.
My Coworker would be Ashe, because she's a good shot.
And my pet would be Cho'Gath, and I'd run out of food in an hour.

I would marry Pantheon, because abs i mean wut
My best friend would most likely be Lulu, we are both crazy that way
My co worker would be Ezreal, for we both suffer form great wanderlust
My pet would definitely be Pix :3

Marry Tryndamere, he has excellent endurance from what I've seen. (and those pecs :L)
My bestfriend would be Hecarim, because suffering is magic, and i like magic (and suffering)
Co worker would be Sona. Seriously guys.
Pet would be Kog. A thousand times Kog.

Marry Janna
I'd be friends with Jax
My Co-Worker would be Fiddlesticks (I hear he likes throwing parties)
and my pet would be Anivia

marry leona, fav champ
best friend would be singed, great drinking buddy
co worker would be rammus because he does what i ask, always
my pet would be volibear because is a bear
if i could have another pet it would be Renekton because he is an interior crocodile aligator

I would marry Caitlyn.
My best friend would be Gragas, FREE BEER!
My coworker would be Mundo.
My pet would be Nasus. Sexiest voice imaginable for a dog.