Hello, I'm quite new to these forums, and I've become a little more interested in cycling in the past two years. My short rides around town are 5-10 miles, while my longer rides right now are ~30 miles at a stretch, all on paved road. I'm not a huge strong person, so efficiency and a light bike are important. Right now I'm riding one of those Wal-mart bicycle shaped objects weighing in at ~25lbs with big fat balloon tires, and full suspension. I am the epitome of slow as you can imagine - In the past week and a half I've done 44 miles averaging ~11mph, w00t! My goal over the course of this summer is to ride a lot and increase my average speed on my current bike before I decide to spend $?-$900 on a bit more serious bike.
I've been looking at the Trek FX line because I'm used to the MTB style bars, but I've ridden drop bars before and I could get used to them if the aerodynamic advantage is big enough. Anyway, I'm basically looking for the lightest frame/wheels I can get (priority 1) and then a good groupset with what's left in the $900 budget (priority 2).
Ideas on other brands/models I should be looking around at before I drop cash? I've been to the local bike shop, and will return to test-ride different models before buying of course.