Yeah eddie was a decent rhythm player. Two others who are good rhythm players are Izzy Stradlin (my fav) and James Hetfield. I don't particularly like where metallica has been going in the last 10 years but I still think he's a good rhythm player.

To add to Dirt's post on adding the bVI and bVII. Another chord that is good to add to your mix is the bIII. It's considered more bluesy but works great in Hard rock progressions. One in particular is "Hey Joe", which I believe is I-bIII-IV-bVI-bVII.