You know, RUDDIGORE's one of the only one's I haven't been in, and I've always found the plot the most intriguing.
I'm going to have to agree with the majority on IOLANTHE. I played the title role my sophomore year and it was probably my most memorable experience doing a G&S show.
I really enjoy THE GONDOLIERS, too... I think the music is more on the "fun" side.
Let it be noted I'm not a huge G&S fan, though. I can appreciate their work, but I'm not fond of actually performing the material.
As for Katisha... I always hear people arguing about how to or not to pronounce it. In the production I was in, the director pronounced it "KAT-i-SHAW" so consequencely, I pronounce it that way. I don't know if it's right or wrong.
"You! You are the worst thing to happen to musical theatre since Andrew Lloyd Webber! And you, well, I just plain don't like you."
~Stewart Gilligan Griffin