Have you played a lot of vanilla minecraft? What was / were (is/are) the greatest thing(s) you have build in vanilla?
I played vanilla for a few months. My best builds were technical. A double skeleton spawner water ladder farm, which collected into a crusher that left them at half health, so a splash potion of healing could generate lots of easy experience. A redstone driven automagic wheat farm where you just had to hold right-click to generate ten wheat a second. I tried to build a long rail-road, and ran into chunk loading issues.