It probably won’t come as a surprise that I watch a fair number of videos about WoW. I play enough characters that I need to rely on the work of other folks to figure out what the best gear, stats, rotations, and so forth are.
Other than Icy Veins, a great site for all this stuff, a new favorite of mine is Preach Gaming on Youtube. A couple of months ago he started posting class guides for every spec for 7.2.5 and beyond. What I really like about his guides is that he explains how things like talents, artifact weapon traits, and abilities all interact. This gives a good grounding for not only what talents you should take in different situations, and different situations call for different talents, but WHY you should be taking them.
Since I found them useful, I thought I would post them here where folks can find them more easily. He posted them in alphabetical order, so I will do the same, starting with Death Knights.