I really dislike these. I like specific questions about specs, gear, etc. but I really don't care for "here's my link, go" threads. However, I'll still take a stab at it.
DPS Spec: Looks fine except drop runic power mastery and outbreak (outbreak is a unholy spec talent) and pick up epidemic and blood caked blade. This will increase damage done drastically.
Tank Spec: Drop subversion (dps talent) for spell deflection (tank talent), I would personally take rune tap over scent of blood, but scent is OK I guess. Move the point in ravenous dead to epidemic, the extra time will let you extend your rotation. I also don't think you need runic power mastery.
Next, professions, get a second one. Good ones for DKs include Inscription, Blacksmithing, Enchanting, Jewelcrafting, or you can do another gathering skill for lots of money. Continue to work on Sons of Hodir, and get exalted.
Finish enchanting your gear. If you have an epic, don't go skimpy on the enchants, go ahead and get the 44 attack power to gloves, the 50 AP to bracer, 22 agi to cloak, 10 stats to chest, and put something on your boots... probably something cheap like icewalker. Enchanting blues has more effect on overall gear than enchanting epics does, but as you're going to replace it, don't spend much money enchanting blues.
COMPLETELY REGEM. Well OK, you've got one gem in your legs that you don't have to replace, but every single other gem in your entire gear has to go. Have two Sovereign Twilight Opals to activate your meta, then every single other socket you have will be pure strength. Strength is, per stat point, the best dps gem for a DK. More than crit, more than AP, more than anything else. Strength strength and more strength. The only time I EVER gem anything except for strength is to either activate my meta, or get me hit capped. Otherwise, strength! Yes, you will be ignoring most socket bonuses. Most suck anyway.