Tank champions would include Malphite, Cho'Gath, Shen, Amumu, Alistar, Blitzcrank and Garen. They're dmg output isn't too amazing if you build tank with them. If you want bruisers (a mix between dmg and health/armor, strong melee fighters) you could grab Lee Sin, Olaf, Volibear can be built a tank or a bruiser, Jax is a good one. Jarvan IV is a tank but can do some dmg if you build him properly.
For first time tanks, I'd go with Shen, Garen or Malphite.
For first time bruisers, Id go with Olaf, Darius or Pantheon.
There are obviously more champions to choose from, I just feel however that these are among the easier to learn at first. Now don't mistake easy for suck.