C.J.
Oh my where does one start?! for the ambiance you are looking for Del Friscos, Reata or Eddie V's, but as others pointed out, Joe T's is great, Blue Sushi, Texas de Brazil or even Yucatan Taco Stand (not really a stand). Silver Fox or Michaels is also good.
I highy recommend Eddie V's though. It is more of a "seafood" place, but they have good steak as well. Sides are served seperate from your plate so you can share - GREAT bar, super drinks, low-key live music - just a great overall experience.
Have fun!!