Alvor, who welcomed him into his home. Camilla Valerius, his wifey! Lydia, his faithful companion. Sorex Vinius. He never liked the man, but they grew to be very close.
And many other friends, scattered across the province.
I always have to stop and chat with M'aiq when I see him. Ralof, since we escaped Helgen together, and his sister helped me out. Kodlak Whitemane seemed like a nice guy, and took a liking to my Nord. Aela is easy on the eyes, and she has her beastial nature. ...that's all I can think of atm.
On my evil character I quite liked a lot of the Dark Brotherhood. I thought Babette and Nazir were alright, Festus was awesome, Cicero is unique, and Gabrielle was cool too. I thought Astrid was alright although I just didn't like how she was moving on from the Dark Brotherhood's Old Ways. Veezara is probably my favourite Dark Brotherhood member along with Festus. Babette and Nazir are good too.
On my Mage I just like nice people. Like Ingun Black-Briar, Camilla Valerius and Muiri (too bad you have to do a certain quest).
There is probably more but I haven't met many people.