Mr. Tuff Dandy

I think I would like to buy my first Road bike.

I want to buy a bike for the following purposes:

- To commute around via the roads of the city.

- To take long rides (i.e. 6-10 hours per ride) on paved trails during some of the weekend days of the summer.

Is a Road bike the best type of bike for me, or should I consider another type instead?

The reason I ask is because I am not exactly sure what the differences are between a "Road bike" and a "Comfort bike," other than that a Road bike has lower handlebars and thinner tires.

I am considering to save up money for a Giant Defy 1. I have read a lot of good feedback about that bike on this site and elsewhere. I have these questions about it:

Question 1: Is the top tube of the Giant Defy 1's frame strong enough to withstand impact? I.e. Might the top tube break if I fall off my bike and the bike crashes into the pavement?

I know very little about bikes, so I am not in a position to judge whether the top tube is structurally sound or not. My question arises purely from my gut instinct: when I look at the top tube, I get the unsettling feeling that says, "that top tube looks awfully thin & brittle on the side that is closest to the seat tube."

I'd appreciate honest feedback about this point either way (that is, to confirm or deny the validity of my fears, whichever is realistic).

Question 2: If I spend $1399 CAD plus tax for a Road bike, is the Giant Defy 1 literally the best bike that I can possibly buy for that amount of money?

If not, what other bikes (brands and models) are either better, or comparable, for that amount of money?

For this question, I am asking about brick & mortar stores that I can physically go to, located either in or near Toronto, Canada. I know that Bikes Direct and Performance Bike have some great deals, but in my case, since I live in Canada, the shipping costs plus illegitimate costs that are added by courier companies to cross-border shipments would nullify those deals.