I shoot in RAW+JPG, so I have my bases covered.
As for in-camera WB (affects JPGs, not RAW), I've used grey cards, Expodisk, and Xrite Color Checker, and setting it specifically as daylight, incandescent, etc in the camera. That got to the point of driving me nuts as I had to continually change settings as I moved from lighting situation to lighting situation at church events. The one that drove me wild was an area lit mostly with florescent lights with incandescent wall sconces and even a couple of LED spot lights. I tried setting the camera to florescent, then daylight, then incandescent, you name it, all without success. Even using a grey card under the florescents and setting Custom WB to that failed as florescents change colors 60 times per second. I ultimately gave up fighting an uphill battle and set it to AWB. That worked pretty well on my 60D. Obviously, AWB outdoors works fantastic. Under 'plain vanilla' incandescents, it works well, too. Everything else...pretty close..except those florescents. So when I wanted to use JPGs to save post processing time, I'd use the RAWs for those shot under the florescents and set WB picture by picture, often using any white thing in the picture...shirt sleeves, table cloths, white polka dots in a dress, you name it, then a small tweak from there. Then export them as JPGs to my JPG folder. In short, I've decided that when I'm shooting in a fixed lighting environment, if I really want to be picky about the WB, I'll use the Xrite Color Checker or the grey card and set it in post. Otherwise, it's AWB and fix what I have to.
But then, I upgraded to a 5D3 last November. AWB all the way...baby. Even under the crazy florescents, the 5D3 AWB is astoundingly accurate! And for the couple of shots here and there the AWB got tricked, I fix those in post. Needless to say, my grey card and Xrite stay home more often than not these days.
And for those shoots or parts thereof I want or need the extra flexibility of using RAW files, I set the WB to white shirts, ties, etc in the picture, and then use the Synchronize feature in Lightroom for that series of shots until I started shooting in another area/lighting.
Bottom line, amateur that I am, I've gotten more and more lazy regarding WB. 'Close enough' is good enough for my purposes and even the free prints and CDs I provide are far better quality than the people in the pictures were expecting as most people are content with cell-phone pix these days. So a real DSLR photo knocks their socks off. Should I ever be foolish enough to take a job for pay, I'll certainly break out the Color Checker and get every shot 'dead on WB'.