After seeing the new trailer, a skeptic asked me:
What's up with Luthor being goofy-insane rather than a Clancy Brown-voiced serious and determined Luthor? Are you cool with that?
What, you mean this Clancy Brown-voiced Luthor?
The point is, every incarnation of Luthor, no matter how self-possessed, is eventually consumed by his irrational hatred of Superman and goes bonkers. Even the corporate businessman version of Luthor invented by John Byrne in 1986 (which inspired the Lois & Clark version and the animated Clancy Brown version) finally wigged out two years ago and showed up in the pre-Crisis purple and green battle suit — all while he was president of the United States!
Actually Spacey doesn't strike me as too goofy or insane. He reminds me more of Buddy Ackerman in Swimming With Sharks. If he shows a sense of humor, it's either affected in order to manipulate people or, when genuine, rather sadistic. In other words, I don't think Spacey is going to be doing slapstick comedy routines with Ned Beatty.
I guess it depends on your interpretation of why Luthor hates Superman. Is he a xenophobe distrustful of aliens, like the ultimate John and Ken (which would prove he's insane)? Or is he a mere con-man who's angry that Superman has thwarted his schemes? Or does he not loathe him personally, it's just that trying to kill Superman is his version of The Most Dangerous Game?
As for Spacey's Luthor, it looks like there is a major spoiler in the trailer if you look closely at the map on the wall next to Lex when he says "Bring it on", which indicates that his ultimate goal is still the same as Gene Hackman's, only cranked up a notch or ten! I almost wish I hadn't noticed it, it's so awesome. Not Power Action Nuclear Punch awesome, but awesome nonetheless.