First "real" road bike was a mid-1980's Univega Supra Sport (bought new). I still have it and someday I will clean it up and take it out for old time's sake. It is stock except for seat, tires, and tubes. I remember buying it because I could stand over the top tube. Not even a test ride!
First real, real bike was a 2003 Lemond Tourmalet bought new last year as a leftover. I rode a bunch of bikes in the same price range and this one felt the best, even though it was a little on the big side. After riding it for a couple of years, and actually learning how to ride a bike like this, I think I would have been better off with a smaller bike.
Anyway, I ride it whenever I have the chance (3 kids all playing sports makes it hard to find enough time). I have replaced the seatpost (very adjustable Salsa), saddle (inappropriate, but *very* comfortable Brooks B17N), stem (80cm), and recently Shimano 105 cranks and associated Bottom Bracket only because I had a slight wobble in the Tiagra cranks that bothered me.
I see no need to get a new bike anytime soon as it does everything I need, but I can see myself doing it for no reason at all.