Space-Time Manipulation. I could put myself in temporal loops (for learning), I could easily build shelters and get food, etc.

Hell I could start my own empire. You said no "escape". You never said other people couldn't be brought there.

Technically yeah, but those people would not get their own powers, since the island didnt bring them.

Which would be even better. No superpowered people = no opposition to my rule.

I'd grow a second skin capable of photosynthesis and keeping me warm. It'd be odd, but efficient.

Sooo.....Plant Mimicry?

Nope. Something new and out of the box. Dermal Armor crossed with Plant Mimicry crossed with Skin Generation.

You picked a weird fucking thing, i suppose it would make for great surviving though.

Unexpected though.......very unexpected.....

My second choice (if I didn't get Space-Time Manipulation) would be Alex Mercers powers, AKA the Blacklight virus.

In such a situation I admit there are a few powers that would be useful to my survival (animal calling and plant manipulation most obviously) but at the same time I on an island (as with any survival situation) survival itself would be ones primary responsibility. That being said once all basic survival needs (food, water, shelter, and a means of keeps oneself active mentally and physically) have been meet than refining oneself would be an excellent way of occupying oneself. That being said providing the necessities of survival would most likely need ones body and mind fit and sharp (respectively) but those would grow routine after a period of time. Once that happened I would begin turning myself into a mystic (through meditation at altitude and self deprivation). After all islands are usually thought of as places of isolation so why not take advantage of that and become as attuned to the natural world as possible. After all understanding how a system works empirically does not mean that one will not over tax said system. On the other hand developing a spiritual and metaphysical connection with a place is a much greater way of assuring that the place and oneself become if not symbiotic at least avoid becoming parasitic.