Let's make sure we're talking about the same thing. The edge of your blade will fold over with use. Running a honing steel on the edge after each use will help with edge retention. Unless you're using your knife daily then you probably only need to sharpen it once a year. Sharpening will remove material from the blade, so frequent sharpening will greatly reduce the life of the blade. Electric sharpeners work just fine for inexpensive knives, but for more expensive blades you'll want to use wet stones or have them professionally sharpened.
As to the original question: most cooks really only need a chef's knife, paring knife, and roast slicer/bread knife. Most all prep tasks can be handled with a chef's. Paring is for detail work or small fruits/veggies. Slicer is for, well, slicing. You might find a filet knife handy if you're cooking a lot of briskets or other meats that need some trimming before you cook. Don't buy a set. I've done that a few times in the past and ended up with knives in my block that I never once used. Now that I own an actual-by-God restaurant, those blades have been repurposed to my kitchen. And my line cooks make regular use of them.
Go to Sur La Table or Williams Sonomo and handle all the knives. Find the one that fits your hand the best. German and Japanese steel are both good. German steel tends to hold up better for inexperienced cooks because the edge angle is not so severe and the steel is not quite as hard. Japanese steel is hard (but can chip more easily) and feels quite a bit lighter.
Find the brand that feels best for you and then hit cutlerandmore.com or chefsknivestogo.com. Those and Amazon are going to be the cheapest places to buy your new steel unless you catch a big sale at a retail store.
I have German and Japanese steel in my knife roll, and I like each for different purposes. I gravitate most to my Japanese blades (Yaxell, Yoshihiro, Global, and Shun) for most all of my prep work. Their construction fits my hand and grip the best, and they fuckers are razor sharp and incredibly nimble. But your results will almost certainly vary.
Lastly, learn how to properly hold your knives. A proper pinch grip and cutting motion will go a long way to protecting both your blades and your fingers.