What's more important to you - packing or cash. If you wish to wear a tux on formal nights you can burn up that $200 bucks in about 3 cruises (depending on the rental rates.) However, in renting a tux it will be cleaned and pressed and waiting for you aboard the ship.
A Bad Day At Sea [with power] Always Beats A Good Day At Work
Alaska 2014 - haven't picked a cruise yet
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, Caribbean 2013