The one that fits you best and made you smile on a test ride
Does the Defy fit you ok if the Avail does as the geometry is different. Will you need to spend extra on changing stems and bars and saddles if you get the Defy? The advanced is carbon, will you be happy with alu if you wanted the carbon? Do you need proper mudguards for commuting, easier on an alu bike, ditto a rack
What's the difference between the 1 & 2? Isn't the 1 a higher spec so why unwilling? (other than extra cost)
Although it looks like you decided so enjoy the bike
http://www.cyclechat.net/threads/bored-of-wairting-for-giant-defy-advanced-2.172475/