I'm not saying this as a Giant fan or anything, but get the Giant TCR aluminum, good frame, full Tiagra groupset (the new one with the more comfy new-style brifters) and the hollowtech crankset. Also, it comes with Eggbeater Candy C pedals so you don't have to really think about getting pedals.
Aside from that, do you have all the cycling gear?
If not, then get the Trek 1000 and spend the rest on your gear; shoes, shorts, jerseys, helmet, etc.

Also, make sure the bike is fitted properly.