I'd start with some socks, arm warmers, knee warmers, and a short sleeve jersey.

I have a light weight windbreaker I also wear that zips up around the neck if it's cold. However, it's not a proper cycling jacket so it doesn't breathe like the expensive ones do. I just wear a cami under my jersey that keeps my core warm.

A lot of people wear knickers or long tights, but I like that the knee warmers and arm warmers can come off and be put into my jersey pocket if it gets warm. My arm warmers and knee warmers are Hincapie Arenburg. They don't fall down like my Pearl Izumi ones did. I don't pull the knee warmers up really high (about an inch or two past my shorts) and they're long enough they go below my calves, nearly to my ankles. I end up with only a few inches of exposed leg.

My hands tend to get cold... really cold. I have a pair of PI long fingered gloves (Cyclone, I think) that I absolutely love.

It's all going to depend on how cold it is and how your deal with the cold weather. I've seen people out in upper 60's - low 70's wearing tights and jackets. Yikes... too warm!