I just started brewing about a month ago. I have done two AG batches so far. I haven't actually tasted any finished beers (2 and 3 weeks away for the two batches), but I can tell you what I did.
I asked myself the same question. Ultimately I want to master the two or three beer types I prefer. (American pale ale, IPA, amber ale, etc). The problem is that just starting out we are in NO way qualified to do that. You can brew beer, and it can be good, but if you have to look up a wiki page to remember how much dextrose to prime with.. well you aren't going to be tweaking the finer parts of an IPA recipe.
So I started with an american stye pale ale. My second beer was an oatmeal stout (something I wouldn't normally order) and I have to tell you it is SO sexy.. it looks good, smells good, and I know it's going to be the first brew that really proves to me that hoembrewing is where it's at. I have the ingredients for an amber ale and an american hefe on the way. For the hefe I'm considering making a few raspberry (at the request of a lady friend), so I'm sort of staring my customizing process there.
I know I want to make the best pale ale and IPA known to man, but in the mean time I'm going to just brew some all around good beers. I put together a batch of apfelwein this morning too.. I have the gear, why not? If I were you I'd make first what you like, then make some **** people are gonna wanna drink to drum up interest. That way you get friends excited, and it spurs you to be better. Just a thought!