Oh god, this rabbit hole.
At the moment, one of these:
I like the Flow shape, it's a good compromize between a Jazz and a full size for me with juyst a little more area than a jazz, but the ultex ones are a bit firmer than I'd like and tend to chirp a little more, even the thinner ones. I like Tortex though, and had been using the "pitch black" Jazz 1.0s for longer than I believe anything else over the years. I grabbed a bunch of the 1.0 tortex flows but found myself wanting a tad more give in the pick, so just grabbed some 0.88s, and they seem like a good middle ground.
In six months, I'll have a totally different answer.