+1 to adding non-combat XP to the list please! There are some great interactions to be had with NPCs, and players should be rewarded for resolving non-combat situations.
From a personal perspective I'd also like to see this: I dunno how it fits in with D&D since, well, I don't really know anything about D&D (so I'm grateful to those who do!) but I've often thought that RPGs in general can be too combat-focussed for my tastes. XP from non-combat stuff goes some way to addressing that.