I would consider NCL, RCL and Carnival to be the bottom of the "fancy" list you describe. Lower prices for the masses. NCL is the least dressy with Carnival and RCL, neither one is dressy any more. You can wear jeans and shorts to dinner now on Carnival except for the "elegant" night (which can be nice pants and capris for women).
I had been thinking you might enjoy a little more upscale .. but not if you dont like dressing up. I would stick with one of the basic lines above.
My usual deciding point is price and .. can I drive to the point of departure. Can you drive to any ports? Where do you live? Thats a huge deciding factor for me.
Conquest 7/21/13, Miracle ALASKA 8/27/13, Miracle HAWAII 9/17/13, Celebrity Summit, 11/30/13, Celebrity Summit, 12/7/13, Celebrity Constellation, 2/7/14, NCL Epic 3/2/14, Allure 5/4/14, Allure 11/2/14, Quantum 12/8/14