Canon: NCIS
Pairing: Tony DiNozzo/Tim McGee
Canon Level: Coworkers

Tim is totally my favorite because he is the tech guy and a huge nerd, and I think he and Tony would be good for each other. They've worked together for years, with Tim gradually growing from a newbie agent to a very good agent in his own right and Tony's been along for that entire ride. They bicker/banter with each other, and Tim can both surprise and keep up with Tony.

Suggested reading:
Shopping Around by kageygirl
Buoy by shetiger
These Things Do Happen by Xparrot