About.com has a great article on the relative merits of different cabin locations on a luxury cruise.
You can read the article here, or to summarize in a few sentences they note that you'll save a lot with an inside cabin and for many that usually-very-tight-space will be just fine since they'll be using it mostly just for sleeping. However they also say a window and balcony cabin is much nicer and a thus a fine place to relax on the ship.
Thanks to the economic difficulties this may be an exceptional time to plan a short cruise, especially if you take advantage of the "last minute" specials that all cruise lines offer. The cruise travel economy is *huge* and very complicated, so the best first start is to surf online to the various company websites to get a basic feel for places, amenities, and costs. I've listed a few of these sites below. After you have a sense of costs and what you might want, dig deeper online searching for "discount cruises" and view several major travel sites for specials and deals. My understanding is that generally your lowest costs will come from specials as they seek to fill a boat in the month or week before the cruise sets sail, so as with almost all travel try to be as flexible as possible for the best bargains.