I like terminal applications, though for flashcards/spaced repetition I personally think a GUI is more suitable. I often use non-text media in this (pictures, formatted math, formatted text). I like Anki's approach where the flashcards are HTML.
Last few times I've looked into spaced repitition, there still didn't appear to be a decent wikipedia style repository of freely licenced, collaboratively produced flashcard sets. Seemed like a missed opportunity.