That's a tough one, there are so many good fictional detectives. I guess I'll go with the combination of Nero Wolfe and his partner Archie Goodwin.
poirot. . .
Sherlock Holmes, L from DeathNote and Kindaichi from Kindaichi case files
im sorry i dont know the ansewer, see you.....oh yeah one more thing..COLUMBO. hes the best of em all.
Columbo and Sledge Hammer.
Sherlock Holmes or Inspector Clouseau.. :)