For tactics I've never seen anything better than chess tempo [0], which is free, or for a small yearly subscription you can absolutely go nuts breaking down tactical themes and combinations of themes, and the tracking is very good. I did several thousand tactics puzzles there and it helped quite a bit.

For books, Beginners Mind by Jeremy Silman is pretty good, as is his endgame book. Logical Chess by Cherenev is also a great introduction to how skilled people think about games but takes a different approach than Silman.

[0] - http://chesstempo.com/