hhhmmm lets see. Zin is a good place to begin to see differences in wine. Most people make zin in about the same way. Viognier is made in many different ways, so you actually taste different wine making styles, like new oak vs old oak or no oak (stainless steel).
So, lets take California's grape, Zinfandel. Zinfandel has no roots to any french grapes, therefore flew under the radar for a long time. There was a myth that it was brought over from Hungry by Agoston Haraszthy, but that was bunk, as he arrived in 1849, and the zin grape was well know in california long before that. It is now believed that it was imported from the Austrian Nursey and DNA testing has finally concluded that is the one and same grape as Italy's Primitivo.
Zin took hold from the California gold-rushers, who had turned to argiculture and that was the homemade wine of choice during the "great experiment" Prohibition.
Zin is relativly easy grow, does well in intense heat and he vines live a long time and have a large yield. THis is a good place to start as the wines are not as expensive as Cabernet.
There are many different styles.
I would recommend:
Rombauer, it used to be named El Dorado, but I don't think it is called that any more, they only make one zin so . .
Ravenswood Vinters Blend. This is the base for inexpensive zin.
Highland "Black Sears Vineyard" from Howell Mt. Might be a bit more than 25, but important to see a high quailty zin.
If you can find it, Turley's California "Old Vines" should be about 25 or 30 bones, but it does get marked up sometimes.
Ridge is well know for zinfandel
EdgeHill makes a classic "claret" style zin from a vineyard in St. Helena called Butala, can be found in souther california,
I don't kow if you want me to tell you about these wines, or you want to taste them and tell me.
Zin will run the range of very full bodied juicy jammey wines, to lighter wines with some acid.
I personally look for flavors of very ripe strawberries and blueberry, sometimes a blueberry pie alamode. Nice spice can also be found like black pepper, or sandlewood.
My favortie, it is expensive, but not outragouse is OutPost from Howell Mt. in Napa. A killer bottle of wine!