So here is a note for those of you who are unconcerned about white balance because you're shooting in RAW...I agree, you can probably leave it on AWB and be fine. Dandy even. However, a couple of my thoughts, my shooting style and my approach...
Personally, I either shoot in JPEG or JPEG +RAW. Never just RAW. I sit at a computer or at a lighting console all day. If I've gone out to shoot, it's for me, and for fun. I don't want to sit and fuss and tweak endlessly with a photo. Especially in just shooting JPEG, it allows for longer burst shots before the buffer is full. To me, shooting in JPEG allows me to rattle off some shots and I'll get the moment or I won't...or maybe I'll have accidentally left it in some strange custom white balance....that resulted in something awesome. This photo was a fun consequence of that:
I was intending to be in a 3200k or 2700k WB preset, but left it in 4000k....but I kind of dig the result. It ends up with the fire and it's resultant light being slightly overly orange and a little exaggerated. It seems like so many people get so obsessed with faithfully recreating what they are seeing with their eye (at least all of the folks carrying around a DSLR who really just want a point and shoot), they don't allow a little injection of art-allow for some funkiness, some fun.
Understanding WB allows you to more fully understand color temperature and how to manipulate it-how to use contrasting color temperature for great effect. I do a lot of television shoots where the host is in front of a white void. One thing that I regularly do is to light the background (the cyc) with a slightly higher color temperature unit, and the talent with a slightly warmer unit-especially if they are very pale. It's only a slight difference-maybe 300K difference, 500k at the most, BUT when we white balance to the background (and the cooler temperature), it makes the talent a tad warmer and richer skin tone, while making sure any reflected light onto the talent becomes an edge that is slightly cooler. This way it presents itself as more of an "edge" than blending with the talents skin tone, resulting in detail loss.
Another very simple reason that it's worth exploring and knowing about White Balance? If you ever shoot video-which is becoming increasingly prevalent on DSLR's, you will be SOL if you've only ever used AWB before. As of right now, outside of R3D with the RED, there are virtually no format of video that allows you the latitude of a RAW file with video.
One last reason that I find I don't like RAW when other folks shoot with it? A lack of understanding of light and color. A RAW file lets you make your white balance ANYTHING. Without shooting a warm/white/gray or color checker card, you are at the whim of your memory to "re-compose" the scene and to properly find a neutral to white balance to. You might be forgetting that the little bit of orange created by the late afternoon sun is why you wanted to take that picture in the first place and will struggle to recreate it.
So hey, shoot how you like. I prefer JPEG because it's the closest to mimicking the mystery of rattling off a roll of film and sending it for processing. There's a little latitude, but mostly what you shoot is what you get. Besides, if you shoot a maximum resolution JPEG, and print it, it's virtually indistinguishable from a RAW....and I just do this to have some fun.
One article I stumbled across that you might enjoy, and another guy who is a proponent of the JPEG can be found HERE.