Bump oh my so many and they have been listed

superman prime (yes the earth 33 whiny as he as i love him)

Overman (god i would buy this comic so bad)

Kingdom come (as many have stated he is just awesome)

hernan (yes new but they one shot and movie were awesome)

President Superman (calvin Ellis)

New 52 supes

I second Hernan Guerra, son of Zod, from JL: Gods and Monsters, as suggested by @saintwildcard. Badass, a bit tougher and more brutal than Clark, but he hasn't gone off the deep end, like everyone seems to think Superman would do if he took a more brutal approach. Showed signs of becoming a bit more heroic towards the end, maybe even using Kryptonian science to better Earth, unlike Clark. I'd love to see those two meet, as most would assume Hernan to be the bad guy standing next to Clark.

So yeah. Other than All Star and Red Son, which have already been mentioned, my favorite is Hernan. I really think he deserves more exposure.

Val Zod for now

Kal-L, Kingdom Come, President Superman and Red Son.

All Star Supes

President Superman

KC Superman

Kingdom Come, Red Son.

Hernan Guerra is also a really bad ass Superman, I really want to see a sequel of that movie. Both Batman and Superman were amazing in that story and the twists were quite entretaining.

Red Son

Overman

KC

Hernan

Calvin

Cyborg Superman

The Eradicator

KON-EL

President Superman is cool as well, I'd like to see more stories about him in the future.

Kingdom Come for me.