Macrumors is one of the best community forums I have come across out there in any subject area. It has a large enough member base so that there is always someone around 24/7, and it is filled with friendly people who are both knowledgeable and kind to newbees. Try hanging around some of the Linux forums... they can be pretty ruthless with new people... goes with the territory I suppose.
Generally most mac owners have obviously thought a lot about their purchase and want to share that enthusiasm with others which is why I think the board is so good.