If I field my DE army, and I will field DoW lords, the are taken as Rare Choice, or Lords choice?

I'm pretty sure you can't take DOW characters in other armies.

If you want to use them for some reason, you'll have to play a pure DOW list.

True? I haven't seen it, when I have looked in WD #251.

*sigh* I get this question a lot. If you look in Chronicles 2004, it does specify that Dogs of War characters may ONLY be used in a Dogs of War army, with the exception of the Truthsayer and Dark Emissary from the Dark Shadows campaign (which are treated as Dogs of War regiments now).

Also, please note that WD250, which has the main DOW army list for 6th edition (the first version for 6th edition, that is), states: Fielding 'Dogs of War' units in other Warhammer armies. It does not say anything at all about hiring Dogs of War characters in other armies. The Dogs of War army list is not like the Kislevite Ally list - you do not need to field a character to use the mercenary regiments, and the 'characters' that are in the Regiments of Renown do not count as characters for the purposes of choosing your army, they are technically regimental champions instead (with the exception of Asarnil the Dragonlord, who technically is a character and takes up a Hero slot). :P