Having always wanted a bike, I think I found the perfect first bike: a 1977 CB750 F2. She has only 17k original miles, still runs great, and was a great deal! I was lucky enough to respond to the Craigslist ad 15 minutes after it was placed, or else I'd have been one of the 50 other people calling in about that bike.
She's also a great first bike because of the minor dings, scratches, and large amounts of dirt, lol, so I am going to get to spend a lot of quality time cleaning, shining, polishing, and playing with the bike, while not being too terrified to take a "show bike" out for a spin.
But the best reason for this being my first bike is the amazing resource this forum provides for tinkering, repairing, and out and out working on my new baby! The wealth of information I've encountered already is staggering and inspiring! I can't wait to really start digging into the guts (carefully) and exploring this machine! I know tools and knowledge will come slowly, but I am resourceful.
I'll post pics of her once she's all shined up, but for now, here is "Martina" (after none other than Martina Weymouth of the Talking Heads) covered in too many years of cosmetic neglect: