Wow. Some you guys are big! How do you fit in your cars?
I agree with David who says you'll want multiple hand positions. I'm moving my hands around my bars after only 20 miles. It really makes having drop bars an advantage.
BlueSide - I truly fear aluminum as a bicycle frame material. I talk to guys with al frames who say they can last no more than 90 minutes - and they're in their 30s.
The components you've cited are good. I've never had a problem with any Shimano componentry; I've put over 2,500 miles on my Ultegra components since early this summer without a hitch.
I'm not a mtn. biker, but I understand myself well enough that I'd probably be cursing the bike's weight in comparison to a hybrid's weight if I were riding it for 150 miles.
If you have some time, maybe you could source the parts for a nice, inexpensive bicycle. Check these guys out:
http://www.somafab.com/somadealersca.html
They have a frame called the Roadie Sport, which sounds right up your alley. The components - Shimano Tiagra - are readily available one ebay, and are very inexpensive for the reliability they offer. I'm sure you could get on this bike without spending more than $700 or $800.