Advice on buying a used bike

Since 2001, over 90,000 cyclist's have joined Cycling Forums to discuss topics from general cycling to equipment, training, racing and travel or vacation destinations (especially in europe during the tour de france). We also feature an great deals in our online store, 100's of articles, classifieds and product reviews.

I'm looking for some advice on buying a used bike. It's a 2005 Specialized S-Works; the person at the bike shop thought it was an E5. They're selling it for a $1000. Pedals might be included; I'll have to check. I'm planning on test riding in the next few days.
It was used for one season by a local pro and it has brand new components and wheels. I was told the frame has a few small scratches, but nothing major (I think it has a carbon and aluminum frame).

I know that how a bike fits is the most important thing, but what else should I look for?
Thanks for your help.

1. Bike fit
2. Geometry
3. Wheels