Morphy,
I agree with much of what's been said above, and I've been down this same road this year. My best advice to you is don't overthink it right now. In March 2009, after having lost about 40 pounds dieting and working out, I decided I wanted to start riding my bike. Without doing much research at all, I walked into a well-respected bike shop and asked them to help me. I walked out with a Trek 7.2FX and started commuting to work. That was at about 335 lbs., and I've not had a single weight related issue with the bike and the only change I made was to put slick tires on it so I could ride a little faster. Twenty pounds and probably 1000 miles later, I went and bought a road bike so I could ride with faster friends on the weekend and also do longer rides. That bike is a full carbon Orbea, and again after about 500 miles I've had no trouble with it.
My advice would be to find you a decent bike from a LBS, start riding, and in 6 months you'll know a lot more about what you want and need. I've learned so much and become such a better cyclist in just a year, and these boards have been a big help, but the biggest piece of it was riding and learning from my experience and fellow riders.
Good luck and go ride. I love it.