I've been a wine fan for a long time, but just recently began to learn extensively about varietals and wine regions. My current goal is to know a little more about the major varietals and the regions they come from. I'm also working on learning the specific characteristics of the major reds - Pinot Noir, Merlot, Cab, Zin, Syrah/Shiraz. I really don't have a preference when it comes to wine in general. I like reds, whites, sparkling, sweet, etc. However, I do have my favorites within varietals and regions. For example, my favorite white so far is a German Riesling. I also love big, jammy California Zins, but I've also started delving into Pinot Noir, and it's growing on me.
There is so much to know about wine - varietals, regions, wineries, culture, history - that you could never learn it all. I understand a wine better when I know more about people and the place where that wine is made.