S30V, D2, M2, CPM-420V/440V, CPM-3V/10V seem to be the top six supersteels these days. Among them, M2 and the CPM stuff is fairly rare. M2, D2 and S30V hold edges very well (probably about in that order), but S30V is more stainless, and possibly a little less brittle ("tougher").
VG-10, ATS34/154CM (basically the same, one's Japanese, the other is USA), ATS-55, VG-10, A2, AUS8, AUS10, 440C, and a few others I'm forgetting, are all great stuff and will treat you well. Most have their own little niche of what they're good for, depending on toughness, edge-retention, stainlessness, hardness, ease of sharpening, large/small blade applications, etc.
The "more common" steels like 5160 (Ranger knives use this), 1095 (Kabar uses this), O-1, W-1, and the beat-around stuff like what Becker Knife and Tool uses, Swamp Rat Knife works uses, and Busse Combat uses, are all mostly for their decent edge-holding but their ability to take a real beating and not snap in half, chip their edge off, etc. These are all also good stuff, just depending on what you need it for. You wouldn't make a scalpel out of 5160, but you wouldn't make a machete out of M2.
You'll find fans of everything out there, so find a few knives you like and if you want opinions on them, post em up, we'd all be happy to weigh in.
There are a lot of steel faqs/guides out there, take a look around. Even just on this forum

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Sorry to talk your ear off
_z
EDIT: In more direct response to your question, yes AUS6 is kinda junky for anything but a beater knife. AUS10 is rare, I only recall one knife (Cold Steel tri-fold or whatever it's called) that uses it. S30V is typically the best of all worlds for a user, so I'd reccomend that to start. But don't limit your search by steel, find what you like then see what it's made of.