1) Metal. He has basically anything and everything I could ask for, and with his infinite technological potential would catapult me in every conceivable way into a positive direction. Not to mention he evolves constantly in real time, so he’ll always become better and more effective.
2) Warp Topaz. There’s no real limit to it so it’s guaranteed to be effective, and teleporting is always going to be a potent ability.
3) Tricore. Recharging is gonna suck, but having the physical improvements from this will always be a good thing to have.
4) Phantom Ruby Prototype. Whilst it’s not a guarantee I’d be able to wield it, since they do have a level of required heart and will, it’s substantially easier than the Chaos Emerald, and Eggman could trigger it just by flipping out. With that in mind, if I could draw out its power, I’d be a God. Due to inability to be analyzed (and thus noticed), I’d be protected long enough for me to get the hang of it. Not to mention if I use it like Infinite, it becomes part of me and allows me to be virtually unstoppable.
5) Chaos Emerald. Really good on paper, but in practice? Awful. They require substantial amounts of Will and goodness in the heart to use “The Right Way,” vary in power a lot, and their techniques require some (read: A LOT) of talent. I don’t think anyone in this Earth could use it outside of a battery, and I don’t think anyone on this Earth is smart enough to turn that battery into the reality warping monstrosities Eggman creates on the daily. Not to mention I doubt I’d be allowed to keep it for long, with it being detectable and generating infinite energy (meaning I’d be a government target). This is also ignoring how hard it is to make it a workable battery to begin with. Generally just not a good option.