bwaylvsong, I did a Carnival cruise in December and there was karaoke every night. The song selection was pretty good but pretty dated - I don't think you'll get anything very modern (in terms of pop music OR Broadwaytunes).
As a young person who's not that interested in partying and who's also done Celebrity and RCL before Carnival, and where entertainment and food are also my highest priorities, I'll warn you not to get your expectations up for Carnival AT ALL. I've been on two Carnival cruises and aside from the discos, they were pretty dismal. (It doesn't hurt that Celebrity set my expectations really high since Michel Roux himself was on board overseeing the kitchen when we went to Alaska!)
The entertainment was fairly satisfactory but not too glitzy. I spent most of my time in the casino because of this.
Can someone remind me again - which line has a better reputation for food? Norweigian or Holland-America? I can't keep them straight but I want to remember because that's the line I want to try next.
And then Crystal!
"It's not always about you!!!" (But if you think I'm referring to you anyway, then I probably am.)
"Good luck returning my ass!" - Wilhemina Slater
"This is my breakfast, lunch and f***ing dinner right here. I'm not even f***in' joking." - Colin Farrell