I agree - buy quality. If you're competitive, you'll be wasting your money on something that will "just do for now." Resale on bikes is very low & how many "go to the store beaters" does a person need?

I ride a custom, so I cannot comment on current bikes EXCEPT that a friend rides a Cannondale Synapse and loves it. It seems very quick & responsive.

This is a perfect time of the year to be bike shopping. With the 2011's coming out, you should get a smoking deal on a 2010.

As for losing weight/muscle - I lift regularly & find it very hard to add muscle. After riding XX number of miles, it's difficult to find the energy to push those heavy weights. Once you start riding, you may find the same is true for you.