Do Fast Lenses Matter Anymore?

The op has T1i - which is noisy at high iso, so the op could gain a stop in improved noise by investing in a

$699 60d

or $600 T4i

I look forward to my next purchase of a sigma 35 f1.4 Art for both my 5d and 60d/T4i

The extra stop and sharp F1.4 will matter to me over the new canon 35 f2 IS and I'll be selling my 35 f2

stopping motion at high iso with a sharp tool and lower noise at twice the ss is what I'm after

op should consider newer body vs faster lens first in this case