http://www.youtube.com/user/darkkiller5000
this death knight is special, very special.
currently, he has soloed the following lich king HEROICS:
Azjol'Nerub
Forge of souls
Ahn'Kahet
Pit of Saron (first 2 bosses)
utgarde pinnacle (up to and including Skadi)
Drak'tharon keep
Halls of lightning
he has also soloed many other things:
Thrym
the icecrown arena quests
doomwalker
karazhan
full molten core
Thunderaan
ToC5 non heroic first 2 bosses
headless horseman
Zul'Aman
Al'Ar
high astromancer solarian
he is currently trying to solo all other heroics, and sartharion.
i think he is the best death knight out there.