Exactly what weapons Death Knights will be able to wield has been the subject of some controversy. Originally, it was speculated by Blizzard that one- and two-handed swords and axes would be the extent of it. Currently in the beta, polearms and one- and two-handed swords, axes, and maces are usable. Daggers, fist weapons, staves, wands, and ranged weapons are not (updated with verified information).
But not many people have talked about what's going to go in that ranged slot. A moment's thought reminds us that every other class that can't use ranged weapons or wands (Druids, Shamans, and Paladins) have Relics in those slots. If you're not familiar, Relics are class-specific items that typically provide a boost to particular spells; they come in different flavors for the different classes. Druids get Idols, Shamans get Totems (confusing, yes), and Paladins get Librams.
Wrath will add one more to the list: Sigils, for Death Knights. So far only one has been implemented in the beta – Sigil of the Dark Rider, one of the first quest rewards in the DK's starting chain. Blood Strike, as far as I can tell, is meant to be a staple skill for many DKs, like Heroic Strike for Warriors, so this should come in handy. And unlike Paladins, DKs have plenty of ranged spells, so pulling shouldn't be problematic – they even have a spell that brings the enemy straight to them, Scorpion-style. Get over here!