I've never ridden a Scott, but Team Columbia-HTC rides them (Mark Cavendish). It's probably an excellent brand if it fits you.
You can see by the craigslist ads that bikes are holding their value really well these days. In your favor, if you make a mistake and don't buy the "perfect" bike, at least you won't lose a lot. It's not like buying a car, where you're out thousands as soon as you're off the lot.
Have fun with the shopping experience. It sounds like you have some great options from your friend's shop.
'02 Eddy Merckx Fuga, Selle An Atomica
'85 Eddy Merckx Professional, Selle An Atomica
'10 Soma Double Cross DC, Selle An Atomica
Slacker on wheels.