As others have noted, do you giggle like a 10 year old every time you hear a name with the word pad in it?
touchpad? launchpad? how about thinkpad? That is a computing name that has been around forever, and nobody ever said, wow that is a sucky name.
Seriously. A few people made a weird connection when the name came out, and most normal people got over it in an hour, and some of you can't let it go.
Given the possible choices of names, the iPad makes the absolute most sense to fit in with Apple's lineup. It was the most obvious choice, for those who are out of middle school.