No one mentioned Cannondale...because some of these guys forget that not everyone knows that Cannondale (And Trek), are pretty much obvious choices.

The Cannondale is likely to be a good choice, but I personally have no exerience with them myself, since I'm fairly green as well.

I currently seem to be collecting Miyatas though, and they are a great ride. I have a 310 and a 912 so far, and I love them to bits.

Nishiki made some quality bikes as well, primarily with Tange tubing. But they also made some low-end bikes. T-Mar can guide you in the ways of the Nishiki.

Final thing: Good goal to try to achieve...since it is the same as mine. But the Gran Fondo near me is 120km...and climbs to a ski-resort...And I'm not a fan of climbs....what's wrong with me?!