Yeah, I guess it depends what you mean by "serious". I have what I consider to be a serious but low end road bike that I bought used for $350. It's a 2005 Specialized Allez and I'm gradually upgrading the components as I find deals on craigslist or Ebay. Late fall and winter are good times to buy stuff.
It now has an Ultegra RD, a 105 crankset and it'll have 105 STI's as soon as I find a cheap and suitable left shifter (I've had a right one for a few months). I'll probably get a newer wheelset in the Fall. Last year I picked up a set of Rolfs for $100. I should have kept them but didn't.
It is and will be my regular commuter until the snow flies at which point I'll switch over to my MTB with studded tires.
I carry a laptop, change of clothes, and lunch in a messenger bag. The bike will take a rack and I even have one for it, I've just never put it on. I'd like to put fenders on it too, but it's not too pressing at the moment.
FWIW I actually see a lot of people commuting on road bikes once the weather gets nice but usually they're 80's bikes or older. I think you'd see a lot more people commuting on them if they were as cheap and common as hybrids or MTBs.
Last edited by tjspiel; 06-19-08 at 10:54 PM.