Personally, I have found the weight of the of the saw a non-issue, {no offense Saw Troll} let me explain. I can cut wood all day with any of my saws: homelite XL,Poulan 2300 cva, poulan 3300, 441. its the loading and unloading of the wood that takes time and energy. If you have power equipment that will do this chore for you then I think the discussion of weight of your machine has credence. In my experience the homelite cuts the smallest amount of wood in a given space of time, but its the oldest, smallest, and lightest saw. The 441 cuts the most wood it is the largest, heaviest [by a small margin] and newest saw. The 441 is what I head to the woods with. Most of my time however, is used loading and unloading the truck, 'cause I do it by hand, lacking power equipment to do it for me.
Having said this. I would get the largest saw that is appropriate for the majority of wood that I cut and wallet will allow. Dealer support and my lack of servicing experience also affect my decision. 7900 or 372 gets my vote.