The Impact of this day, stretched across every Borg story that came after it, and always will. Especially if you read the books; they carry everything on, and it is worth reading trust me, they attack again, in force, and wipe out planets, no prisoners :S And this is why the Borg are scary.
I always considered the Borg to be a force of nature. Okay, I added some spiritual/religious themes to my Polarisverse, then again, after DS9, who cares Anyway, in my interpretation, the Borg is the personification of entropy, it was, is and will be. Yes, you can wipe it out, do a Caeliar on them, but in a time, maybe a decade, maybe a millenium, the Borg will be back.
Nayy, Sir, I refuse to accept this new wave of Trek books. Worf having his upteenth woman, Picard and Beverly having a son (how the frag? They are around 80 by the time of those books!), Riker captaining a flying zoo, Ezri Dax of all people getting a transwarp ship... bleedin' hell no! And don't get me started on Vanguard! That took a bigger dump on the spirit of TOS then Abrams ever could.