This is a question that has no real correct answer. Kind of like when my wife asks me if a skirt makes her butt look big...
We've sailed on 6 ships in the past few years and have three more booked for 2004. Here's my opinion. Wear what you want. Period. You are on vacation, and most will dress nice for formal evenings. I wear a dark suit, tie and hard soled dress shoes. I just do, it makes my wife happy, and that is good enough for me.
The added values are great family photos, it feels nice to dress up for something besides the people in my office and more.
On warmer weather cruises I have changed to other clothes for the evening events. We usually go to the theater show in our nice attire and then change to nice shorts and collared shirts for the late evening. The casinos are smoke filled and I don't want a to smell that on one of my suits.
I've worn khakis to dinner on formal nights on the Majesty of the Seas and many did as well. We had just sailed from CoCo Cay and it was hot. Few were dressed up.
Carnival has a more relaxed dress pattern, and on the Celebration, Ecstasy and Elation I wore starched khaki shorts to dinner on the nights we were in port. You do the math, a full day of snorkeling, sun and beach and we wanted to shower, dress in resort casual. After dinner we walked off the ship for a some last minute shopping and a frozen drink (or two?) at Fat Tuesdays.
Confused? I hope not. You are on vacation, it's your money and if someone is offended that a 46 year old man wears nice golf style shorts to dinner then close your eyes while I walk to the table and invoice me for the financial damages you've endured.
Finally, we have sailed on two consecutive Thanksgving cruises and most all dressed nice for dinner on formal nights. In about three weeks I will give you an update on what I saw on the Rhapsody from Galveston.