I'm no expert on the trek line, so I have no real input on which bike to buy, but I suspect most of the ones you're looking at could be great -- see if the shop will let you take it on a test ride of your nemesis hill. Also-- be sure you're using your most efficient gearing at the appropriate times; I can't tell you how often I see people riding uphill on their smallest cog, pushing with everything they have, while I'm spinning in a larger cog and on a smaller chainring, making much better speed up the hill. I presume you're beyond this sort of newbie mistake, but it never hurts to ask :-)

I want to put another plug in for determining what is weighing down your 7100, though. I would think that a bike spec'ed the way the 7100 is would be ~30lbs, give or take a couple (I suppose the 'womens' frame could add more weight to give it stiffness, and that suspension fork isn't light, but more than 10 lbs? that seems like a stretch). That's without rack, fenders, accessories, etc... My Kona Dew Drop is ~27/28 lbs naked (weighed oh so scientifically on a bathroom type scale ;-)), and I think of it as a reasonably heavy bike. Adding a rack, fenders and various other accoutrements brings my weight up above 35 pounds (and then I add another 20-35 lbs in my panniers). The rack is the biggest culprit, by far. My point is, you could get a bike that weighs closer to 20 lbs, but then add a 5-10 lbs rack to that, and you may have lost much of your advantage, and you may give up some comfort, durability and a lot of money ;-)

Either way, though, new bikes are always nice to have, so whatever you decide, enjoy it!

I was going to jump on the gearing bandwagon, but your 7100 should have a 28 tooth small chainring and a 34 tooth largest cog, so I wouldn't think there'd be much room to improve there --