Grant, MIRI is a good one for sure.

I like the early first season episodes with Yeoman Rand (Grace Lee Whitney).  I think it would have been interesting if her character had stuck around for the entire run.  I heard conflicting stories--problems with alcohol, a desire on the writers part to "free" Kirk a bit more with his intergalactic romping (though it didn't seem to really stop him too much before she left, they just didn't have her in the episode or not prominently so).  Perhaps both are true?  Anyone know?