The first one I would like to recommend is the website – www.songsterr.com – which has TABs with stems and also includes a playback option of different instruments. TABs on the web would never be accurate, however this site might be one the best free TABs you can find these days. It also includes premium features like speed and tuner, but they’re not essential. I refer my students to this one, which for me replaced my old recommendation – www.ultimate-guitar.com
The second is www.guitarbackingtrack.com which has almost 800 tracks that you can play with. One of the major problems that any guitar student encounters is the lack of playing with other musicians and although it’s always best to play with live players, backing tracks are a good way to practice, especially in terms of rhythm. In addition to known songs you can type ‘Blues’ in the ‘Song’ search bar, for instance, to find blues tracks which a guitarist can’t live without. Also, there are many jam tracks here: http://www.guitarbackingtrack.com/bts/Jamtracks.htm
Another nice website is www.guitar-tube.com which consists of guitar videos but requires registration in order to see them. It’s a great tool if you are looking for videos of a specific guitarist like Paco de Lucia, for example, to get some insperation http://www.guitar-tube.com/guitarplayers/paco-de-lucia
Hope this helps!