One of the first things I said when Disney bought Lucasfilm was that anything not produced by Lucasfilm (basically all of the Expanded Universe) would officially be outside of Star Wars Canon. For all practical purposes, this means the 6 episodic Star Wars installments (surrounded by scripts, novelizations, etc) and any offhand comments made by George Lucas. I know some people don't like it, but George Lucas is basically god when it comes to anything he said or did while he owned Lucasfilm.
That makes today, March 7th 2014, the first release of official Star Wars canon from Disney with the release of Star Wars: The Clone Wars Season 6 on Netflix. Actually, the entire Clone Wars series is on Netflix now,
- G-canon If it is in the current 6 episodes, novelizations or scripts of said episodes, or was stated by George Lucas prior to (possibly also after) the Disney acquisition, it is irrefutable Canon (remember, I'm taking exception with the George Lucas "Han Shot First" loophole here). Fortunately, The Ewok Adventures get bumped from here since it isn't episodic, and therefore slides down to N-canon.
- T-canon This canon level is currently occupied exclusively by the Star Wars: The Clone Wars TV show and the upcoming Star Wars: Rebels TV show
- C-canon Most of the expanded universe is here. Books, comics, games, etc. Any event that is contradicted by G or T canon gets dumped to N-canon. Characters are not necessarily entirely N-canon just because a portion of their story is contradicted.
- S-canon Any Star Wars stories that are not a part of Star Wars continuity, but do contain backstory or lore that doesn't conflict with higher canon falls here. This is typically Star Wars MMOs like SWTOR or SWG.
- N-canon Basically a parallel universe. Star Wars: Infinities comics (by definition) along with any other crossovers. Also, anything that conflicts with all higher canon.
A lot of supposed die hard Star Wars fans roll their eyes at the mention of this show, but give it a shot. There are a lot of concepts the Star Wars movies have never been able to explore (many of which I mentioned previously) that are chronicled in The Clone Wars. It isn't strictly a "kids show" either, as it does explore some more mature themes.
I have yet to watch any of season 6, but I liked the rest of the show. It appears that season 6 could actually be the most useful addition to canon and serve as a better bridge between the prequels and the Original Trilogy.
So, be a purist if you want. You can only explore your favorite corner of the sandbox if that's what you prefer, but Star Wars is like pizza for me. Even when it's bad, its awesome.