That depends on what you're using it for. Kitchen knives and bushcraft knives have different criterion.

I wanted to experiment with very high grit abrasives for sharpening, but needed an economical approach: I used contact cement to secure 150 and 400 sand paper to some pieces of marble and glass.
Results were mixed, more experimentation is needed. This is apparently an approach used by carpenters to achieve scary sharp plane blades.

As I have clearly stated on here, I do not like serrated edges and I'm sick of commercial makers putting them on everything. And in the worse possible place on the blade. I have a S&W fighter and sure enough they ruined it with an inch and a half of serrations. I have an old Sea and Land serrated folder with my climbing gear. Thats the only one I approve of. Just my opinion. You are all entitled to yours.

For kitchen knives I like SRS-15, Aogami Super, Shirogami (White #1 or White #2), AEB-L & some tool steels that seem to be proprietary. The steel in the Kagayaki CarboNext at JCK is awesome for the money. 19C27 is also very good. In the hands of someone who knows what he's doing, like, say, Devin Thomas, then 52100 is about as good as it gets. Very soon I'll be trying a new gyuto in M390 MicroClean. I have high hopes for it. Lastly, if you have the big bucks then ZDP-189 is superb.

I think VG-10 is pretty good for outdoors-type knives. CPM154 is pretty good, too. S30V is a good strong steel but doesn't take as good an edge as VG-10. In the hands of someone who understands how to heat treat it correctly D2 is a great steel (but off the cuff I'd only trust Bob Dozier and Knives of Alaska). O1 is a really good steel, and I particularly like JK Handmade Knives (I've got 50 of them). 1095 is acceptable but not premium. I shy away from 440C and its' variants...not crappy but there's much better. There are a few higher end ones that get good press but I can't speak from experience. These include CPM-M4 and Boeler K390. Someday... Busse does a good job with his proprietary INFI steel. And surely there are some obviously great steels that I'm simply forgetting right now.

You need a certain level of quality of steel but really I think that, within reason, the heat treat trumps the choice of steel.

That hasn't been my experience.

Press the quote button at the bottom of any post and you'll be able to see how it's done in UBBCode -- it's very straightforward. PM me if you have any issues.

OK, all you sharpening wizards, I have a question about sharpening at the other end of the scale. Let me explain.

Every July for the last decade or so, I have served as crew chief for excavators digging mammoth fossils in the Black Hills of South Dakota ( here). One of my routine jobs is to sharpen tools, typically chisels, pointing trowels, and putty knives. Typically the tools dull rather quickly, as we are digging in fine grained sediments. I often will sharpen the same tool twice a day.

The current "sharpening" technique consists of running the edge along a medium grit bench grinder, taking care not to burn the steel and occasionally dousing the tool in water. My interest is heightened because I have just acquired a hori-hori, a Japanese tool fashioned specifically for digging dirt. It is rather dull, and I am sure sharpening will improve it. but I am thoughtful about the best way to put a good edge on it. The blade is inscribed "K245 Stainless China'" which is probably not in the same league as S30V. Any inisghts are welcomed - What is the best way to sharpen an edge for really rough work in dirt and rocks?

IMHO, this is the fundamental pattern for all knife and gun discussions.
Intelligent, educated, experienced well-intentioned people disagree as to ideal configurations, and choices are influenced by marketing, media and historical forces. Knife utility is often a function of user skill and proper application, as has been suggested by the OP.

On this forum, tool preferences approach the status of religion; religious debates can become heated, with partcipants burned at the stake.
It might be wise to agree to disagree, and to preface all comments with traditional formulations of humility IMHO/YMMV.
Kumbaya, My Brothers and Sisters, YMMV.

There's only so much you can do in a high-wear environment like that. Digging tools use milder steel and are heat-treated for durability rather than edge-holding. Regardless of method, you're going to be resharpening on a regular basis.

I would certainly stay with a single bevel. It's not elegant, but it's faster to do and will probably wear longer. The angle of the bevel is a trade-off between penetrating ability and how long the edge will last. 45 degrees is the simplest and probably the best you can do in that application.

I sharpen all my digging tools by hand, with a 10" mill bastard file. For digging tools there's little value (IMO) in doing anything fancier. Frequent touch-ups keep the sharpening job from getting too big. If I'm far afield, a coarse diamond file does the touch-ups.

With a bigger fleet to maintain, hand sharpening probably isn't practical. A bench grinder or angle grinder will build up heat with frightening speed, even using the lightest pressure and fast passes. That's why knife knuts use a 1" belt sander. You could try Norton's white aluminum oxide wheels for bench grinders, designed to run cool(er) for sharpening tempered steel http://www.nortonindustrial.com/BenchPedestal-WhiteAO.aspx .

But consider also the contrarian view: when using a bench/angle grinder (with extreme care), the heat you generate will create a thin edge that is harder than the core steel of the tool, and will last somewhat longer. You'll know you've done this if a file bounces right off it. But if there is visible burning/blueing, you're doing damage.

Your new hori-hori may be a special case. I'm not familiar with that steel. It's probably a single bevel right from the factory, and you should follow those lines. But please use a file or diamond. I hope you won't put it on the grinder.

(Long post, sorry 'bout that. Practically a Sunday sermon. )

In the old days, I was taught to sharpen a scythe with a hammer and a stake anvil. blades get dull when the edge is turned-cold hammering returns it to shape without the loss of metal incurred by grinding and filing...
...and you get to whack something with a hammer, which might be therapeutic, IMHO, after a full day riding herd on young paleontologists. YMMV.