Well All-Star, Birthright and Red Son are literally my absolute favorites, along with Kingdom Come, another elseworld, so I had to give this one a little more thought, lol. Assuming TPB's are acceptable as well...
-Action Comics, Vol 1 - Superman and the Men of Steel by Grant Morrison
-Action Comics, Vol. 2 - Bulletproof by Grant Morrison (this one's not as good as it's the "middle chapter" of Grant's run and the final part won't be collected into a TPB until later this year, but I just loved his run)
-Lex Luthor: Man of Steel by Brian Azzarello (I guess technically an elseworld, but still pretty standard universe, just from Luthor's POV)
-Superman: For Tomorrow by Brian Azzarello
-Superman: Peace on Earth by Paul Dini
If you're not looking for a ton of depth and just want some straight-forward action-y stories, Geoff Johns' stories work for that, Superman: Brainiac being a good example.
A lot of the best older stories are, to me, single issues that can be found in various TPB collections, like Must There Be a Superman by Elliot S. Maggin (Superman #247), For the Man Who Has Everything by Alan Moore/Dave Gibbons (Superman Annual #11) and What's so Funny About Truth, Justice and the American Way? by Joe Kelly (Action Comics #775). That last one's not that old, but you get the idea.