Bench grinder, tool sharpener or sharpening stone?
All of those are suitable tools for sharpening woodworking equipment, from chisels to plane irons to drill bits (certain types).
Note on sharpening bits: most woodworkers don't sharpen their drill bits these days. Partly this is because many won't dull their bits noticeably in any reasonable timeframe, but also because many modern bits are not user-sharpenable (at least not easily).
Traditional wood bits were made of relatively soft steel (soft enough to be filed), of a form that allowed access by a small file and last but not least an easy replication of the necessary angles. Modern bits are mostly shaped such that you couldn't file them freehand and expect to get anything like the required accuracy, and also some are high-speed steel (HSS) which will usually be far too hard to file anyway.
Some previous Questions and Answers with related information:
Is there a 'best' way to sharpen an edged tool like a chisel?
Does it matter what kind of diamond stone I get?
Sharpening grits -- naming and selection
How does one aggressively sharpen chisels and plane irons when damaged?
What criteria would want me to bevel my chisel in a certain way
How can I tell if wood turning (lathe) chisels are sharp?
DIY honing oil?
These are considered the basis of sharpening for many, but equally other woodworkers don't have one after decades in the shop so as vital as one might seem it can be considered optional. Desirable certainly, but not vital for all woodworkers.
Why you'd need to use a grinder is very dependent on what tools you use (as well as if you buy secondhand tools which can require far more metal removed to get into serviceable shape) and how you use/abuse them. I stress need here because wanting to use one to reduce the time required to sharpen is a separate issue.
Sharpening stone (with or without a guide)
Stone here refers to both stones and diamond plates which are used similarly.
This is the default way to sharpen in many, perhaps most, woodworking shops today. In almost all cases you can effectively sharpen any dull hand tool in a few minutes or less — the goal should be to return to work in 2-3 minutes, and it is possible to do it faster (30 seconds or so).
Whether exclusively hand sharpening is an efficient use or your time is dependent on various factors.
- The way you sharpen, e.g. honing a secondary or micro bevel or working the whole bevel.
- The type of stone/diamond plate. Some are much more abrasive than others but note that this isn't necessarily because they're harder. Waterstones are famously fast-cutting but this is not because they are very hard but because fresh abrasive particles are exposed often as the surface wears away.
- The type of woods commonly used. Hardwoods in general are much harder on cutting edges than softwoods and some species in particular are extremely wearing, often due to a high silica content.
- The type of tool, e.g. turning chisels need to be sharpened much more frequently because of the way they're used.
- The steel the cutter is made from. Some steels are far tougher than basic high-carbon tool steels and can also be harder in some cases.
Note that sharpening guides (also called honing guides) are not a must-have. You can sharpen very effectively freehand. But if you struggle to get good results, if you sometimes get a good edge and other times not, it is a good idea to make or buy a guide to help get good edges now when you need them.... not at some indefinite point in the future when you get good enough at freehand sharpening.
If you want or need a guide I strongly recommend making your own as they can be very cheap and effective, and believe it or not can work as well as any commercial guide irrespective of price. This is the best type IMO because it is so simple to make, costs nearly nothing and is capable of extraordinary accuracy:
Note that there are multiple types:
- some water-cooled, some not;
- some have vertical wheels, some horizontal plattens such as the WorkSharp 3000 you linked to, some use abrasive belts;
- some are very low-speed machines (so work slowly to very slowly), others are faster but use cool-running abrasives or design features to keep temperature in check (including water cooling).
For most woodworkers any machine of this type should be considered a luxury. As with any luxury get one if you can afford one, but don't sweat it if you can't. They are very much in the Not A Necessity category for most of us.
You didn't ask about stropping but as you're setting up to sharpen from scratch some mention of it should be made.
Stropping (whether using a bare strop or one loaded with compound) is an adjunct to other sharpening methods and as touched on in one of the links above, should broadly speaking be considered a honing or refinement process, not a sharpening process in and of itself. However, a 'dull' tool can be brought back to razor sharp just by stropping (esp. if using a stropping compound) so the distinction is a little blurred.
What matters on a practical level is just how dull the edge has become. Past a certain point — when the edge has become too rounded — you won't be able to get a good sharp edge only by stropping. It's for this reason that people who are big proponents of stropping for edge maintenance (e.g. many whittlers and carvers) will have a strop on hand at all times so that touch-ups can be done as often as needed (every 20 minutes in some cases).
If you strop frequently you'll rarely need to sharpen your chisels in the conventional meaning of the word, so they'll rarely see a stone or diamond plate. With regular use and a bit of luck you can reduce the need to sharpen by a factor of ten or more, stretching the interval from days or weeks to months.