Sharpening is a little like German or French bow -- there are slightly different ways of arriving at good results, and there are general principles that guide you no matter what method you're using.
MJE's method is known as the "Scary Sharp" or dry abrasive method.
Rather than go through a whole rigamarole of explaining sharpening theory, I'd recommend a great book: "The Complete Guide to Sharpening", by Leonard Lee, founder of Lee Valley Tools and sharpening guru. Great for general principles and the electron microscope photography.
Grinders, manual or motorized, are for rough work, shaping the metal as opposed to honing it. Motorized grinders are a great way to burn the temper out of tool steel and thus ruin them. I use a rough diamond stone where a lot of folks would use a grinder. Takes me a bit longer, but I don't worry about burning metal anymore.
Once ground to shape, metal edges are honed using progressively finer abrasives. These abrasives can be stones (natural or man-made, oil stones or waterstones) or some kind of sandpaper.
Your strop is good for final honing/polishing, especially if you used some kind of honing compound in conjunction with the strop.
Really, there's a ton of ways to do it. Learn the general principles, pick a method that appeals to you (for money, for aesthetics, whatever) and get a bunch of practice.
I've got all kinds of sharpening doo-dads I've collected over the years, but these days I usually use just the rough diamond stone for shaping and a two-sided waterstone for honing. I keep the honing stone handy to the bench, because I like to hone a lot while I'm working. I think it's better to hone more often with less fuss than it is to hone less often with a bunch of rigamarole around getting a "perfect" edge. You need it sharp enough to do good work, you don't need it perfect.
Sharpening is one of those skills that woodworkers are always extending: sharper, faster, cheaper!! You need to find your way of doing it.
Oh yeah: honing guides are a great idea. Lots of old-timers will scoff at you, saying it's not necessary. IMHO, they will really help a beginner get good results faster. Get a guide that has as wide a roller as possible -- there's a common inexpensive one out there (Stanley? can't remember) that has a roller that's way too narrow. The guide tips too easily as a result.