The 7d of course has significantly better autofocus, more akin to a 1d series. It also has more and more sensitive sensors to do tracking with and more processing power to do computations - but a lot of it comes down to technique.
and lenses. To be honest pol024, your lens lineup is not known for stellar AF performance.
The 7D has 19 cross point sensors, the xxD line has 9, Rebels have 1 cross point sensor (center only). The cross points make AF quicker and more accurate.
I have noticed very little AF accuracy between my 7D and T1i with the same glass on it (24-105L, 135L, 50 f/1.4). I did notice a slight improvement in IQ and high ISO performance when I made the jump. What this tells me is that good glass will get you farther in photography than a bigger and better body.
I have paying clients for sports and photojournalism, so the advanced AF was important to me. If I was a consumer/hobbiest, the T1i would easily fill my daily needs. If I wanted something more as a hobbiest, I would be at the xxD line.
