Kennen
Jax
Gangplank
Akali
Rammus

Blitz, Ram, GP, Yorick, Twitch
CC and tankiness, movement buff champs, 1 group movement buff, 1 death harasser, 1 stealth just for kicks.

Sona
Soraka
Taric
Karma
Alister

Because you can't beat up a team that can heal themselves up to full all day long.

Closer.

Rammus is usually banned, as are Akali and Jax.

Ryze is pretty powerful, but also can be countered fairly easy with the right champions.

XZ is overrated and dies quickly to the right choices.

My top picks would be:

Heimer (if not banned), Galio, or Teemo to defend bot.

Poppy or Sion
Nocturne or Gangplank
Pantheon
Shaco
TF (if player is good with him) or Caitlyn/Vayne

Some other champions that are good:

Singed
Kog'Maw
Riven
Wukong (a good one)
Xerath (a good one)
Talon
Kayle

Good movement, good damage, global ults, tanky/sustainability.

Any team with all tanks....seriously try it out...grab 4 other people and pick a team of all tanks (rammus, renekton, shen, sion, malphite, maokai, allistar, amumu, leona, poppy, singed) any of those i swear you wont lose...between all the taunts, stuns, and armor/health no one on your team will die...and if they do they take forever to kill if built properly you can build a tank/ap or tank/ad on dominion fairly easily

With the normal->Rammus/akali/jax/hei-shaco bans
-Yorick(Bot)
-KogMaw.
-Riven
-Gankplank
-Blitz/Twich.

bot: Heimer, Poppy
mid: Blitzkrank
top: Yorick, Gangplank

Jax-For obvious reasons
Xin-Only really beat 1v1 by Jax
Karthus-Godmode defender
Akali-Ya no
Rammus-Rolls very quick, like ninja.

As has been stated:

Poppy
Any other four champions of your choice.

Miss fortune
Rammus
Nocturne
Pantheon
Akali (OPali)