Modded vs Vanilla

Personally, I like both. If I had to pick one though, modded Minecraft would definitely win. A well-built and balanced modpack can be played for weeks, if not months without getting mundane. The problem with Vanilla is that after playing it for a while you get bored, having nothing more left to do and having the best possible EQ. In addition, if no major update comes out, the gameplay will soon become repetitive each time you start a new game/world. Unless you play multiplayer or with friends, of course.