The size of your pot will largly depend on what you want to cook. This determines the amount of water and expansion space of any dehydrated food. For freezer bag cooking (just warmed up) generally a cup less is good. Remember, a full pot does little good because you are always spilling hot water/food, but remains the same for 1 or two people.
So, for solo work I figure around 3 cups. A K-Mart grease pot is my pot of choice for solo. I think these are actually 4 cup (1quart or about a liter) capacity, counting the overflow.
With a partner, I have a 2qt aluminum pot I got about 40 years ago,about 5.25"x5.25". Something comparable would be:
http://www.campready.com/default.asp?SID=xCK4JCM8VAFHSQPTSDYWYE&S=503&A=E&PKV=13160|0
Bail handles are easier than side handles around the fire and stove, just prop them up, over the pot, away from the flame. Pick them out of a campfire with a stick.
Aluminum dents easy, but is much lighter than titanium. Titanium gets it's weight savings from it's thinness, due to it's additional strength. But, the thin ones are prone to cracking/breaking. Aluminum will dent, ti will crack. I have broken a pot on a slip in some scree. I used my cup for the rest of that trip.
Ti cookwear generally has aluminum added, soo, you are not getting away from aluminum, if you subscribe to that line of thought.
Conductance is slightly better than with Al, about 1% acording to R. Coffin. Again, this works both ways, so, it doesn't really matter. I feel it is significant when multiplying by the amount of heat needed to boil water. Roger says not.
Acid can attack aluminum a little quicker than ti. If you are cooking marinara sauce, you might want to go with ti, otherwise they will impart a taste to the sauce.