Better "go to" lens other than 18-55?

i'm about to purchase the t2i along with the 50mm/F1.4 lens (for portraits, food pix and that blurry effect). i also need a good zoom lens that'll be quick enough to capture my running toddler and will produce good quality photos.

i don't need a huge zoom, something average. is there a lens you could recommend that's better than the 18-55 and will fulfill my purpose? i keep hearing from friends that bought the 18-55 that they were not very happy with it.

thanks in advance!