I really think New Krypton was a great concept that just spent too much time twiddling its thumbs, until just recently when they got going with the 'Last Stand of New Krypton' stuff. Superman and the Legion of Superheroes vs. General Zod and his faction vs. Brainiac and Lex Luthor? You have my attention, sir.
On the subject of Superman and his villains, as potentially awesome as Lex Luthor should be (the smartest and richest guy on the planet, is ballsy enough to repeatedly pit himself against one of the most powerful beings in the universe, etc), he's never really had himself a real "holy shit this guy is fucking awesome" moment. Like, the Joker has had a few moments that just blow you away for how far he's willing to go (killing Jason Todd, crippling Barbara Gordon, etc). Brainiac has been made out to be quite the badass since his return (particularly when Superman finally meets the real Brainiac for the first time, and Brainiac just plain beats the crap out of Supes with his bare hands). Darkseid has had more than his fair share of awesomeness, Zod has his catchphrase (and a whole army nowadays), even comedy villains like Bizarro and Toyman have had their time in the spotlight. But there's never really been a time when I've been just floored by some awesomely evil thing that Lex Luthor has done.
Well, aside from the episode of Justice League Unlimited where he beats the living shit out of the Question for catching onto his scheme. The fun starts at about the 3-minute mark here: