In Shadowrun, the best roleplaying I've had in the past few years was a very complicated run. We were hired to retrieve what turned out to be a horrific, fast-acting bioweapon. We ended up deciding to turn it over to the UCAS government rather than Mr. Johnson.

Turning the weapon over to the government without getting killed, arrested, or appearing on the evening news truly involved a lot of roleplaying. In addition to just carrying out the many steps of saving our asses, we also found time to take photographs of a nude Mr. Johnson the male dwarf albino mage in a coffin motel. (Both were covered in duct tape residue, Mr. Johnson was drugged into oblivion, and the dwarf had a lot of stun damage that left him exhausted and vulnerable to blackmail photographs.) Getting the bioweapon turned out to involve little combat, just the infiltration of Seatac airport and reaching a locker. However, there was a lot of footwork, a lot of wheeling and dealing, a lot of involvement of contacts, and a lot of fun.

Combat, as I recall, was minimal, but that's common (though not universal) in the best roleplaying sessions.