When I had that decision to make, I went from the T1i to the 60D, and for me it was the perfect step. I got the added control functionality that I wanted at a price which didn't break the bank. The T4i would not have worked even if it had been available at the time, because I was after the control ergonomics more than any feature enhancement. The only thing I see with the T4i is enhanced video AF and that means nothing to me.
Originally Posted by Kryten
With the 60D I went from 15 to 18 mp, better ISO performance, and the top LCD and top buttons, as well as the back dial and dedicated back button focus. The flip screen is handy but wasn't a deal maker or breaker. All for less than $1000. I even looked at the 7D but it was more expensive and didn't offer anything more that I needed. Since I already had the SD cards for my T1i, I was set. The 7D would have required changing to CF. I also didn't want the larger, heavier body of the 7D. I don't need the extra FPS (5 with the 60D vs. 7 with the 7D) that was the only real advantage I could see with the 7D.
Anyway, I went 60D. You need to evaluate your needs and decide what works best for you.
Canon 60D; EF-S 10-22 f3.5-f4.5 USM; EF-S 17-55 f2.8 USM; EF-S 60mm f2.8 Macro; EF100mm f2.8 L IS Macro USM; EF 70-200 f4 L IS USM + 1.4x II TC