So, we're ourselves but get to inherit an X-characters power set?
I assume limited to mutants only (no Gladiator, Juggernaut, etc). And no extra stuff, as in, if you had Logan's healing factor, you wouldn't automatically have his adamantium skeleton/claws, just bone ones.
Man, it's hard not to pick Xavier and have near absolute power via telepathic control or mind reading. And power corrupts, and absolute power corrupts absolutely. I dare say I'd be bad with it, and therefore, a villain. So, I'll forgo that temptation.
Honestly, Magneto's powers would be hard to pass up, and man you could really do some good with them. Ironic that I'd be good with the villains powers and bad with the heroes. Most X-mens powers would suck to have tbh. One could have Storm's power and basically be a force for good around the world providing rain in drought areas, averting hurricanes and tornados, putting out wildfires, etc.