The Cessna 152 is the best basic trainer. The rent cost less than a 172 and the 152 is in the "utility category", which means it is built to take extra G's. Also you can spin a 152 ,unlike many other planes like cherokees and 172's(at full weight) which are not spin certified. Although the 152 is not fast and the cabin is very small, it is a docile flying machine with few bad habits.
The C152 without any question. I know its tiny compared to the 172 but you learn basic "stick and rudder" flying beyond a doubt. Plus, you can spin it and I think everyone should have actual instruction in spins and spin recovery. After solo, the 172 is a good introduction to real world flying and a great airplane for instrument training. Consider a few hours instruction in a taildragger just to broaden your experience.
Beechcraft BE-77 Skipper! Actually, I learned yesterday that the one that I train in (N3857J) only has a year or so left on the wing spar with no kit to repair or replace it, so, in about a year or two, my flight school is going to get a 4 or 5 plane fleet of Cessna 172's... perhaps 3 older, high time ones for training, and 1 or 2 really nice ones (with the nice GPS's) for flying friends around in.
I started my training with a C-172 but then went on to finish my PPL with a PA28-140. I liked to PA28-140 very much. It is a very stable aircraft and talking about spins, boy can that airplane spin and the good thing with it is if you mess up on the spin, all you have to do is let go and it will recover.