I like "I, Borg." Even though you could argue that it makes the Borg a less formidable enemy, I still think it was a great story in the classic Trek tradition of turning a situation on its ear and making you really think about it. It, unlike many of the other episodes, doesn't actually neuter the Borg because we're not talking about a change to the collective. We're talking about one drone being disconnected. And though the implication at the end is that Hugh's change could affect the whole collective, we don't know that for sure.
OTOH, I hate "Descent." Loathe it. And do I really need more reason than the season-ending cliffhanger being "The sons of Soong have joined together. And together we will destroy the Federation." Ugh. All Lore needed was a black hat and a mustache to twirl. The whole thing just falls flat to me.
As for FC and Voyager, I think they destroyed the Borg. Now, that's not to say I found them unenjoyable. I think FC is a good movie, and I like some of the Borg episodes on Voyager, particularly "Scorpion." But that doesn't change the fact that they destroyed what was great about the Borg. The whole notion of the queen takes away, IMHO, from the fearsome nature of the collective whole.
The entire notion that FC needed a character like the Borg queen is, really, lazy writing. It's being unwilling to think outside the box of needing a single devilish antagonist that we can see, speak to, and quantify. It would have been much more creatively satisfying, as well as uniquely Borg, to work within the parameters of the Borg not having a single leader and being a hive mind. There was even some of that in the decision to make Picard turn into Locutus, but at least that was executed in such a way to make it dramatically compelling. Much more so than, say, the Borg queen trying to seduce Data. Ugh.
I guess what I'm really saying is that I prefer the Borg of "Q Who?" to just about any other incarnation, though I can't deny that "Best of Both Worlds" is one of the best Trek has ever produced. But they just gradually got more and more neutered until the Borg were little more than any other villain, with their evil mastermind leader and her minions.