The most powerful versions of.... (Part One)

Darth Vader: Dark Dimension Anakin.

In the Darth Vader Comics, Vader figures out how to bring back Padme from the dead and upon entering the vision loses his armour and gains two Lightsabers. The challenges included killing all the Jedi and watching Obi wan being killed by Palpatine. Eventually he reverts back to the form of a 22 year old Anakin and confronts Padme but she rejects Anakin.

Spider-Man: Captain Universe.

In an accident in Peter Parkers experiment went wrong his costume was cosmically changed into the Captain Universe outfit by the Uni-Power. This form gave him incredibly enhanced spider-senses, strength, speed, flight and limited telekinesis.