This is my first cruise that includes formal, semi-formal and pirate

dining - we're trying to keep our luggage to a minimum because we'll be in Europe for 3 weeks. Any ideas? Do most people really dress up? How much would a guy in khakis standout? My 16 year old and 12 year old love to dress up - my 13 year old and 44 year old won't be as excited.
I don't know what you will be doing for your other 10 or 11 days in Europe - but if you're doing some moving from city to city - I would limit your luggage to ONE moderate sized (21x14) suitcase per person and one SMALL carryon (13x10) that can be "attached" to your suitcase. We are visiting 4 cities before catching the ship in Barcelona and that's what we are planning on doing.
The guys:
* Formal/Semi Formal night(s) - a dress shirt, tie, slacks
* "Normal" nights: Polo shirt and "dockers" and/or slacks (remember that the clean polo you put on for dinner tonight can be worn on shore the next day - only need one shirt per day instead of two!!)
* Pirates night - see "normal" night
* daytime wear: in attempt to "blend in" (but we'll be the ones with the cameras and saying "look at all of those old buildings"

) we are wearing slacks and polo shirts on our touring days. Considering getting some of those "convertable/zip off leg" pants.
* shoes: ONE pair of reasonable looking comfortable black shoes (maybe all black tennis shoes, or Ecco or Rockports. Also will bring one pair of sandals or thongs (oops... I mean flip flops

)
The gals: (ok, so this is much more difficult

but...)
* Formal/Semi Formal night(s) - a dress, or nice pants suit, but probably better would be a skirt and blouse
* "Normal" nights: Skirts, capri's and blouses - coordinating, but different so you don't/won't be wearing "the same thing" every day/night (I know how much you hate that

). Bring a couple of scarfs to change the "look" of your outfit.
* Daytime wear: see "Normal" above. Here's where the scarf can also come in handy - many churches (Vatican especially) require knees and sholders to be covered. If you are wearing a sleavless blouse, a scarf can be used to cover your sholders, and if you're wearing shorts or a short skirt, a scarf can be wrapped around your waist to get your knees covered.
* Pirates night - same as normal
* shoes - OK, you can take as many as you can fit in YOUR suitcase - no fair making anyone else carry your shoes.
For everyone
* one swimsuit and one pair of shorts - for when we need to cool down.
* toiletries: as minimal as possibile and as small of a size as possible - purchase refills as needed before the cruise.
Most of the above comes from the
Rick Steves travel site - our plan is to pack as light as possible.
Link to his Travel Tips page
Link to Rick's Travel Bags (a bit pricey - but you know that they are going to be high quality).
Link to the
most valuable/important item to take with you on your trip and how to use it (
click on the Money Belt link - the packing one is good too!)