I think the whole point of there being just one cube at the beginning was to show us how damn powerful The Borg were, that they didn't "need" more than 1 cube to take on 29 Federation Ships without a scratch.
First Contact would have been better with more cubes and a DS9 "Sacrifice of Angels" level of Federation ships to fight them. I'm happy we got what we got though, considering that's the best TNG movie, and that's not saying much.
The whole idea about using Picard against The Borg was kind of expected, but the genius comes in at Picard himself being the one who gives them the solution with his "sleep" statement. I freakin' loved that! It was great that everyone thought he was just exhausted, while Data actually deduced the true meaning of it.
As for VOY, Scorpion I and II were great also, particularly for successfully one upping TBOBW. In the one, we have an enemy so powerful that it whacks the Federation in 2 mins. In the other, that same super powerful force meets a force so much more powerful, that it's whacking *them* in 2 mins. The ending of Scorpion 2 was good, but I wish it would have gotten fleshed out and not so rushed to get the episode to end.