ok, tyr mentioned that since we now know all races can be death knights, then we should probably have a more serious race discussion thread when it comes to death knight race. so heres my take on things, from a min/max perspective.
alliance races:
dwarf - eh, decent. the second best tank out of the allies with stoneform to knock bleeds off, but otherwise the racial advantages are meager. you get a useless gun bonus (since i doubt DK's wil shoot anything; theyll just bring whatever they want to eat to them), some negligible frost resistance that decreases in relative power as the level cap goes up, and treasure finding, which while nice in some cases, isnt a factor when min/maxing.
draenei - id rate these guys about middle of the pack. gift of the naaru will help for leveling and outside of arena pvp, and can help a bit even in pve, but DK's wont be stacking huge amounts of +healing or spell power, so its effect at the end game will be far mitigated. still, a free heal is a free heal, and sometimes all you need to win is 100 more hp than the other guy, so id call GotN a wash in terms of gain.
the shadow resist and JC are like other resist/profession gains; nice, but ultimately negligible in the long run. id imagine DK's would get a +hit aura instead of +spell hit, and thats always nice, but its nothing a draenei warrior or hunter doesnt already provide.
gnome - probably the best choice from a pvp standpoint. you get escape artist which is huge for warriors and rogues, so it would stand to reason that it would be equally huge for another melee class. gnome DK's will probably make mages cry like few other classes can, as not only can a DK negate blink with an inherent ability, but being gnome provides an escape mechanism against nova, and the lichborn talent (if it remains as is) would provide immunity to polymorph. the only thing a gnome DK lacks is offensive dispel of some kind, which could prove problematic if the RNG works against the DK (frostbite/impact procs mostly).
more eng skill isnt terribly bad or good, but it would give starting gnome DK's a neat little advantage in terms of professions. the rest of the gnome package is rather lackluster for a DK; more int means nothing, and negligible arcane resist, while nice because its arcane, is still about as meh as dwarf frost resist.
human - human DK's will be, hands down, the best from a pve dps perspective, and probably from a tanking one too. the increase in expertise is huge; the other three racials are just frosting really. perception is nice from a pvp standpoint, and will make rogues sweat since a human DK can go lichborn + perception and find a rogue without fear of being sapped or stunned. the spirit buff is nothing to write home about, and the rep gain aint bad; it just means human DK's spend 10% less time grinding rep.
night elf - night elf DK's will he hit or miss; theyll either synergize really well with creative use of shadowmeld, or it just wont work well together at all. shadowmeld is traditionally a nice racial in world pvp and bgs, rather useless in pve (save for the odd afk where its a hassle avoider) and near useless in arena. as a melee class without a charge, shadowmelds usage will likely be relegated to breaking ranged cast time spells while out of combat, which is a niche use at the best.
the nature resist is like all other resists, wisp form is great fun for taunting your friends after a wipe and not much else, and the dodge passive helps a bit for tanking (but not, imo, as much as the expertise does).
final alliance tally:
pve tanking -
human
night elf/dwarf
draenei
gnome
pve dps -
human
draenei
dwarf/night/gnome
world/bg pvp -
gnome
night elf/human
draenei/dwarf
arena pvp -
gnome
human
night elf/draenei/dwarf
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horde races:
blood elf - mana tap and arcane torrent would be the big bonus of being a blood elf. a 2s aoe silence is quite powerful in a coordinated group, and gaining runic power back, even if its only 15 points at a max charge, cant be a bad thing. the enchanting bonus is like all other profession bonuses; nice, but nothing gamebreaking, and the chromatic resistance is slightly better than other resistance bonuses in that its 5 to all resists instead of 10 to one, and you rarely face situations where only one resistance is an issue. still, 5 is even more negligible than 10, especially with the increased level cap.
orc - orc DK's will hurt. blood fury racial bonus + axe expertise + command will make for some monster pve dps DK's. more ap, better dps from axes, and more damage from ghouls are a min/maxers dream. the stun resistance is just icing at this point. tanking orc DK's will be nice and beefy too, with a passive bonus to stun resistance added in with the expertise making for a creamy mix of tanking goodness.
tauren - tauren DK's will be pretty monstrous as well. war stomp gives another stun (albeit one on DR) and adds more control over casters (possibly as a way to force mages to blink before gripping them back). the passive HP bonus will make tauren tanks the premier "new content" tanks for the horde. for hern and nature resist, see above comments about profs and resists.
troll - troll DK's will be similar to dwarfs imo; rather meh. the berserking bonus will probably eat runic power, which may or may not be a good thing depending on how abundant it is. berserking also suffers from the constraints of only being truly effective at low health, and low health is exactly what most people want to avoid regardless of the situation. still, from a soloing perspective, given the plethora of self-healing a DK looks to have, zerking might actually be pretty decent. let yourself get low, hit zerking, then heal back up to full as you grind.
bow/throwing expertise is nothing, and regeneration is still poopy (unless it somehow synergizes with DK self-healing abilities in some unforeseen way, which i doubt it will but you never know). more damage vs beasts is actually not too bad from a pvp perspective; troll DK's might be able to make druids pay for going into their feral forms. the question is, will the troll make them pay more than an orc could? my gut feeling says no, but again, its hard to say for sure early in the game.
undead - undead death knights are a natural fit. from an aesthetic perspective, whats cooler than being an undead guy walking around with your own army of undead, risen from the bodies of your slain foes? maybe if the army was comprised of undead puppies or something, but theyd have to be really badass puppies. from a more serious perspective, undead fit about the middle of the pack. WotF will be nice in pvp and tanking as another fear break that doesnt require using lichborn, and cannibalize is always nice for pvp and soloing, but in terms of pve dps undead probably sit near the back. orcs and trolls will put out more raw damage thanks to their racials, while even belves will be able to gain from runic power every 2 minutes with torrent.
underwater breathing is kinda nice from a pve or world/bg pvp perspective, and the shadow resist is like all other resists.
final horde tally:
pve tanking -
tauren
orc
undead
troll/belf
pve dps -
orc
troll
belf
tauren/undead
world/bg pvp -
tauren/orc/undead
belf
troll
arena pvp -
belf/tauren
orc/undead
troll
thoughts?