I prefer summer. Not that I dislike fall, I just dislike knowing that winter is on its way. And I prefer late sunsets.

As for preparation, you'll want some layers to add or subtract as weather conditions change and you warm up or get colder during a ride. Arm warmers, wind breaker, wind vest, base layers, stuff like that. Capris, knee warmers, leg warmers or tights, toe covers if you're prone to cold feet. I personally find that wool garments are the most versatile for fall, winter and spring, and I know I'm not alone in that.

There's a bike shop near where you live called Bike Doctor. I've never been there but many of my friends in the Oxon Hill club shop there and have nothing but great things to say about them. They can be helpful with suggestions for cool weather clothing (and lots of other things). And of course the good people at Team Estrogen have just about everything you could need and they can provide good, specific advice about their products if you have questions.