Aluminum will weigh less than Fiberglass for the same size. And if properly cared for will outlast it as well. My 16' Lund is still going strong after 30 years of service. Very few dings, but then I tend to be careful around rocks.
A lot depends on where your going to be paddling. A lake canoe will often be longer with a good keel, with less rocker, designed to paddle straight. Where one designed for rivers will have little or no keel, a lot more rocker in the hull and be more agile in fast water. But they won't paddle straight across a lake as well.
Also it makes a difference if your just paddling around your home lake or if your planning to go on trips with it. For a canoe that just stays home fiberglass would be ok. However if your thinking of hitting Minnesota's boundary waters or other wilderness you want something that is a lot easier to portage. On a quarter mile walk over stones and through tree's ever pound counts up fast.
If its just you paddling you might consider a entry level kayak instead. If you just want something to get you out on the water to fish, etc.
I have 3, all molded plastic, all about 10' in length. They sit closer to the water than a canoe does, but the feeling of freedom and mobility is awesome.
Also a good entry level kayak will run half the cost of a good Canoe, weigh less, and be easier to cartop or transport. And yes they do make them with built in points for rod holders, tackle storage etc. All reachable from the seat.
Take your time, do some research now so when you do buy your not sorry a year later.