Sugar is a cohesive ingredient, but as long as you have SOME sugar in the mixture, you can cut down on the sugar up to about 3/4 LESS than what the recipe calls for without any "side effects" on standard recipes.
I too prefer to taste the cake rather than the sugar. I always use less sugar in my cookies, cakes, and other pastries and have never had any problems with them.
The more "gourmet" the recipe though, the more exact it is on what it must require. If this is the case, then you can substitute artificial sweetener for some of the sugar. Depending on what artificial sweetener you use, will depend on how much sugar you can leave out.
If you want to use less "sugary" sugar, then you can use brown sugar. It is sweet, but it is not as pungent as refined, granulated sugar. Some people prefer to use brown sugar, as they claim they still get something sweet, but it "doesn't hurt your teeth" or "have that sugary sweetness".
If you do try out using brown sugar, be sure to dissolve it completely in the liquid you are adding to the cake mixture BEFORE you add it to the dry ingredients. Brown sugar can be coarse and lumpy and very grainy. If it's not completely dissolved before it's mixed with the dry ingredients, you run the risk of a "crunchy" cake or having hard lumps in it.
You can also substitute honey for sugar. Again, make sure it is dissolved into the liquid before adding to the dry ingredients.
As for ratio's, well that is something you have to experiment with, as your taste will be different from others....so what might work for them is not necessarily what will work for you.
Just remember, if you use frostings and icings on your cakes and cookies, you really don't need a sweet cake or cookie, as the frosting will be pretty much entirely made of sugar. This is why I like shortbread or sugar cookies, as they are mostly flour with very little sugar, because these cookies are designed for being frosted...so they don't turn out sugary sweet.