Yes Wrath of Kahn is great and (along with First Contact) is probably the darkest version of Trek. It's generally accepted among Trek fans that the even numbered movies are better than the odd numbered ones. So Kahn is nr II, nr IV, Voyage Home is quite fun and more tongue-in-cheek than the others. VI - The Undiscovered Country has some interesting political drama between the Klingons and the federation (very much a cold-war reference).
I guess Nemesis broke the spell of the even numbered movies being good. Esp if this new one (which will be XI) turns out to be good