I agree with this sentiment in that buying a new bike gives you the option of riding several different sizes to find the one that fits you best. Current 105 is going to be superior in many ways over 2003 Dura Ace. Remember the technology trickles down with time, so current 105 will share features of 10 spd Dura Ace/Ultegra from years past.

I disagree with those who say that more gears doesn't make much of a difference. It's really nice to have closer gear ratios. It allows you to shift the front less frequently. If at any point you decide you want a cassette with a little bit larger range the gaps are going to be closer with 10 spd than with 9.

A new bike with Dura Ace components is going to cost some serious coin, and I would advise against spending that much on your first road bike.

I dunno, $800 seems like a lot of money to be spending on a seven year old bike with outdated components on what is now considered to be more of a entry level road frame in Cannondale's current lineup.

I'd consider going with a Caad 9 (if the local shops still have them) or a Caad 10 with 105.