Star Trek II the Wrath of Khan 
The best of them all.
Great action, great characterization

Star Trek III the Search for Spock 
Almost the worst of the batch
It sags more than my bedsheats.  Only saving grace is Lloyd as the Klingon

Star Trek IV the Voyage Home 
Good but not great.
Campy and self-depricating.  Smart humor (ie no fart jokes).  That last one is a good thing.

Star Trek V the Final Frontier 
Proves that even God hates Shatner.
The very worst one in the series.  You can't get much worse.  The Beavis and Butthead Trek dream sequence had more intelligence than this load of spit.

Star Trek VI the Undiscovered Country 
Not the best, but close.  A bit of a combination between IV and II.
Even after twenty-five years, Kirk can still jump twenty feet in the air to save the President.

Star Trek Generations 
or the Death of Roman Numerals
Drivel
Every Trekkies' wet dream.

Star Trek First Contact
Okey-Dokey
Not bad but not good.  I'm so sick of the Borg, I've erased the word "assimilation" from my vocabulary in protest.