I've always wanted to do a front handspring double front tuck vault personally. although it seems crazy, i just learned a fhs tuck, so i guess one step closer there.
on bars front giants have always seemed appealing, but I think I would die of happiness if I learned a pak-shiposhnikova. again, i have the pak, so i guess the easy part is there, i just need the super crazy part!
for beam, i'd just love to learn some kind of no handed skill (not a jump, lol). hands are extremely overrated on beam, and they always get in my way
and on floor, i think a double layout is really cool.