ORIGINAL SERIES
Neon Genesis Evangelion - Original 26 episode TV show
Director's Cut - Episodes 21' to 24' (a few new scenes, not that important)
Death and Rebirth - A recap and then half of EoE. Ignore.
End of Evangelion (EoE) - Finale for the show, aka Episodes 25' and 26' (COMPLETELY different to 25 and 26)

REBUILD OF EVANGELION
Evangelion 1.0: You Are (Not) Alone - Mostly a rehash of episodes 1-6 but better
1.01 - Fixes some lighting, 1.11 - Improves pacing near the beginning, a few minutes longer
Evangelion 2.0: You Can (Not) Advance - Fantastic movie, diverges considerably from the original.
2.02/2.22 - Minor improvements I guess.
Evangelion 3.0: You Can (Not) Redo - A total disaster.
3.33 - The movie was so fucking atrocious that they figured no amount of editing could salvage it and went straight to the final version.
Evangelion 3.0+1.0 - Who fucking knows when this'll come out.