If you're too cheap to spend $35 to replace the fenders, you should probably not be looking at Treks anyway. Before I even took delivery of my Portland, I had SKS P-35s installed. I kept the Bontrager Satellites, and put them on my Litespeed. To me they weren't "terrible, useless" commuting fenders, they were free roadie fenders. They're perfectly fine on my roadie for keeping my backside stripe-free when the roads are wet after a rain, or even on nice days during the winter when I might come across some meltwater.

As for the aluminum, living in the rust belt, I wouldn't own a steel bike for a commuter. I do own a steel bike--a '99 Schwinn Peloton. It comes off the road in early November and it doesn't see the road in the spring until after a good gully-washer or two washes the salt away. (Maybe next week sometime, we had some good rain yesterday and today.) Meanwhile, the last time I didn't bike commute was before I bought my '06 Portland. It's delivered me to work and back home on every workday in seven salty winters without complaint. It rides better than the steel Schwinn too.