Oh, man, talk about a slippery slope! Over/under, automatic (or "gas gun"), and more - 26-inch barrels or 32-inchers, 1-dram load, or 1 1/8, 7.5 shot, 8, or 9, chokes that range from cylinder to full-plus and more - but it sure is fun. I caught the bug a few years back and before I knew it, I found a great sale on a Browning o/u. I wound up buying that, along with a full set of chokes that I mostly, now, do't change much - improved modified in the bottom barrel, full in the top.
And the games are all really different. Skeet is really fast, and works well with a shorter barrelled gun; trap has its own complexities, especially when you start shooting handicap and doubles, which I don't. Yet. And sporting clays can be especially infuriating, especially when the range changes the presentation every week so you can never really learned the dag-nabbed place.
I shot clays in Scotland a few years back and found that it's a different deal, there in the UK, than it is here. It's all good, though. A really great sport that plays right into the affection for tools and hardware that we all seem to have.
For much more on all this, you might want to go to
shotgunreport.com, I think it is. The guy who writes that blog there is Bruce Buck. He really knows his stuff, and is a very entertaining writer.