I'm of the mindset that it's always better to train on "steam gauge" airplanes, and then to transition to a glass airplane. There are several reasons to this, but the main two; you gain better situation awareness when you are not being shown where you are. You develop an internal map if you will. Not to long ago I was flying with a client in his G1000 Synthetic Vision equipped. Despite all the technology at his disposal, he still busted airspace. Another reason, other than the fact that it's far easier to transition from standard instruments to glass, there are far more airplanes available with the standard six pack.
As what airplane is best suited for you, I mostly agree with Rickair777, with the exception of using the diamond twin star. I would rather train in a multi engine that challenges a student. The twin star is pretty easy to fly compared to other twin trainers. This isn't to say that twin trainers are difficult to fly. My experience of the Seneca is that it's a remarkably nose heavy airplane on landing, but not a bad platform to train on. Both the Dutches and the Seminole are tried and true trainers. As for ATP and ATP style training centers, I would run a search for them here on the forum to see if that is the type of place you would like to train at. Personally I'm not a fan of that form of training. But that's just one opinion. One of my current students used to train at KISP, if I remember I'll ask him what he thought of the school there. Actually I suppose he's no longer my student since he passed his checkride not 5 min ago