Whitch to choose?

I want to start at the warmane as a DK!! I like to tank and make a nice dps as tank too!! witch i choose blood frost or unholy??
Second queastion is is retri paladin good dps at this server??

DK tanks are one of lowest "tank dps", not like tanks need dps. Blood is great and easy to play as tank, but all specs are able to tank, so choose what you like and stick with it. I see many new guys changing spec every day and making alts while they suck with all of them because they just don't give time to get good with spec.
Retri is pretty high dps for such "supporty" spec.

Good luck.

Thank you very much for the reply!! :D

Play for fun and pick upi what give's you more joy the rest is not important