My favorites are Del Frisco's and Capital Grille. I also like Ruth's Chris and go to them in cities that do not have a Capital Grille or Del Frisco's. BLT Steak is also very good.
I have been to Morton's, Palm and Flemings and do not like them as much. The best steak I have ever had though was from Craft Steak in the MGM Grand in Las Vegas.