The whole original series.
picard as the borg and the first time we see the romulans in NG
DS9 tribble episode
enterprise mirror episodes (wish they would of finished it off with that instead of the crap they threw together)
Nothing about Voyager (besides 7)
Khans reveal and attack. death of spock
final battle in VI
Most of mine are space battles, but the ones that aren't:
Riker and Worf fighting the Admiral in Conspiracy (most of that episode if pure win anyway).
Picard's "this far no further" speech in First Contact.
Sisko's diary during "In the Pale Moonlight" and his reasons for doing what he did. Quite possibly my favourite moment, and imo arguably the best acted/written star trek scenes ever.
Almost anything with Q.
Data's laughing gift from Q.
Data trying to save Lal with such ferocity that even the admiral was forced to admit defeat.
Yesterday's Enterprise (the whole alternate universe).
TNG Future Imperfect (yeah, i likes AU's).
The bridge fight from DS9 "The Search".
Worf deadpanning (it happens a lot).
Archer getting obsessed over stopping the Xindi (Quantum Leap guy had some great scenes).
City on the edge of forever.
That's it for now...
"With the first link, the chain is forged. The first speech censured... the first thought forbidden... the first freedom denied – chains us all irrevocably."