Where is a good place to go on a cruise?

I'm looking to go on a trip with my girl. We would like to try a cruise. I have done them with my family before, but I was very young and don't remember much. Where is a good place to go? We were thinking western carribean. Any thoughts? We would like something cheap (obviously) but most cruises themselves seem fairly priced. It's getting to the port that is the expensive part... We are flying out of Chicago, so as long as the airfare is cheap, we're all for it! We like the sun, swimming, anything cultural, and all inclusive is nice too :) Any suggestions or personal experiences would be much appreciated. Also any suggestions about which cruise line to go with would be nice. Thanks!