I was reading through the new feats, and it looks like you could put together a pretty crazy combo as an at-will attack. It does require paragon tier, though. The combo is:
Dragonborn fighter wielding spear and shield.
Tide of Iron at-will attack: 1[W] + str, push the target 1 square
Spear Push feat: Push the target an extra square
Polearm Momentum feat: Knock the target prone (because you pushed it 2 squares)
Draconic Arrogance feat: Deal an extra 2x str modifier damage (once for pushing the target, once for knocking it prone)
So you now have an at-will attack which is effectively:
Hit: 1[W] + 3x str modifier, push the target 2 squares and knock it prone
Dragonborn fighter wielding spear and shield.
Tide of Iron at-will attack: 1[W] + str, push the target 1 square
Spear Push feat: Push the target an extra square
Polearm Momentum feat: Knock the target prone (because you pushed it 2 squares)
Draconic Arrogance feat: Deal an extra 2x str modifier damage (once for pushing the target, once for knocking it prone)
So you now have an at-will attack which is effectively:
Hit: 1[W] + 3x str modifier, push the target 2 squares and knock it prone