I've been playing on and off for a long time but I've always been self taught. Man, I wish I would have paid for some lessons back when I was 15 and I was making some scratch.

I have problems picking fast which usually manifests it's self most when I'm skipping strings while alternate picking triplets.
I've played around with different picking styles but I never settle on one style long enough to really see if I've found the proper technique.

I have a natural tendency to twist my pick so that I'm not flat-picking. This tends to make me pick faster as the pick tip slides over the string but it's not as clean or accurate. I get more of a scrape-scrape-scrape rather than a pick-pick-pick.
Looking down on the string from the front of the guitar it would look a bit like this:
string ===========//============
// <-- pick

(I hope this is a mono-spaced font)

When I try to flat-pick I notice I have a tendency to move the pick in and out. The pick hovers over the strings and dips in to hit a sting. If you were to lay the guitar flat and look down the neck at my pick the tip would move in the shape of a WWWWW or uuuuuuu. I hope that makes sense. This seems natural to me because when I'm bobbin in and out it just takes a bit of exageration to clear a string between strokes if I need to skip strings (doesn't work all that great in practice but that might just be me).

When I watch people like Paul Gilbert alternate pick fast I'm seeing another style that I have a lot of trouble with. It looks like Paul keeps the pick the same distance away from the body of the guitar and he picks back and forth with the pick face flat to the strings. This style is difficult for me because it forces you to pick hard, especially with a thick pick. It does allow you to keep your wrist from having to twist. The only motion required is up and down.
It also seems, to me, to make skipping more difficult because you have two distinct movements.. side to side and them the hop over the string.

Which is it? Is this completely a matter of personal preference or should I be focusing on one technique over another?

thanks for the tip.

You know.. I think I've seen this a while back. :-/

What about the bobbing that I tend to do? Do most people pound through the strings?

It sounds like Paul nails them when he's picking fast. That seems a bit counter intuitive though because it would cause more resistance. I've seen a lot of fast alternate pickers who are really slamming the strings when you hear them with the amp turned down.
Should I focus on up-down-up-down or should I be bobbing in to get the string on each stroke.

He uses a sort of floating arm technique (with usually with his elbow on the guitar) and through sheer practice he's managed to get the ability to use tiny movements with the extreme tip of the pick combined with extreme speed and hence thats what you see there