We've been on 16 cruises so far (and still counting.) I don't know if Diplomat Don is a long time cruiser or a newbie, but he pretty much hit the nail right on the head in his first post, other than he left out RCCL. RCCL is the best bang for the buck, but it will also be a step below a few of the other cruise lines.
Cruising for us is a very economical stress free way of traveling. I wouldn't call it an adventure (like RV'ing on your own) it's more like going on vacation where your parents were in charge. Just plain touristy fun, interspersed with some corny down time.
We took a reposition cruise from Alaska down to LA near the end of August. Much too cold to spend time on deck when north, but very nice once we got down south.