- buildings,
- scenaries (holiday),
you need wide lenses, like 17-55 but it cost a leg..or you can go with sigma 18-50 or tamron 17-50. there are some ultra wide as well.
- night shots/low lighting,
you need a prime lens.
- macro shots...
It's not that hard to focus then recomposing using a 50 1.4 @ 1.4 with a distance of 2-3 meters away, @2 meters you get a DOF of about 3.5 inches. @3 meters you get about 7.5 to 8 inches of DOF, having that..even you tilt your cam a bit when recomposing your subject should still be in focus...