My nr. 1. Favorit couple is Castle& Beckett from Castle. 2nd Bones& Booth from Bones.
Then in no particular order: Olivia& Peter (Fringe), Lisbon& Patrick (The Mentalist), Grace& Wayne (The Mentalist), Chuck& Sharah (Chuck), Rizzoli& Isles (Rizzoli& Isles), Auggie& Annie (Covert Affairs), Andy& Sam (Rookie Blue), Gail& Chris (Rookie Blue), Tony& Ziva (NCIS). & i have a few Mehr but my hands hurt ;)
At the moment the two couples I'm really addicted to are 1) Fitch/Sanchez-Detroit 187 2) Goren/Eames-Law & Order: Criminal Intent Can't really decide Favorit between them because the first is so cute and quirky, but I've liked the Sekunde for a really long time and if Du watch the series Du can tell they're practically soulmates, well both are but with them it's really obvious.