Steel is important enough to me that I admit to buying knives I didn't really care for just to try the steel. The reality of the steel's performance rarely lives up to my expectations and it's not always due to "hype".
Some of my favorite steels are Super Blue, 52100, O-1, W2, White steel, Vascowear, 3V, 10V, and a few others.
The High speed steels are some of my favorites as well. CPM M4, and M2 are wonderful steels. They are able to do everything I like well . I suppose if I had to live with one steel for all uses for the rest of my life I'd take M4.
I've never been much of a stainless guy but I do have respect for some of the stainless steels. Lately I've been comparing and learning 390PM, and Elmax. Between the two I can get a better, more savage edge with 390PM while Elmax will take lower angles for such a high alloy, high vanadium steel.
BG42 has always been a favorite. I'm really looking forward to the Powder steel version of it that will be used by Spyderco in an upcoming sprint. I have high hopes for it. I also like VG10, S30V at RC 60-61, CPM 154 at RC 61-62.
The sandvik steels take nice edges very easily. Aus 6 will sharpen about as easy as any stainless.
For monster wear resistant stainless steels I'll take S110V. I like it better than S90V, S125V, and S60V, all of which I have knives in. The only problem noted is the s110V is not near full hardness in either and it doesn't get full potential from the steel. I have a custom on order that should correct that, joining my others.
The edges I get with these may last forever but my real favorites are the Tungsten containing steels. Super blue and vascowear are two examples. They seem to sharpen up to a savage, tearing edge very easily. They last pretty well too.
Joe