..does the aircraft have a significant impact on the learning and skill development of a student pilot?[/QUOTE]
..My opinion after 30yrs flying / teaching..Get your initial training in a light 2 seater (f.ex. C150/152 or a similar taildragger)..Flying these planes will require more rudder control and coordination, so at the end you will come out as a better ``rudder and stick``pilot..After that, the more exposure you get to different aircraft (old vs. new, glass cockpit, high perfomance, turbine etc.), the better of you will be as you get ready to fly commercially..Do not turn down any opportunities to get time in a new type, if you have a chance to go fly..Good luck !!
Fly safe,
B-757