I thought mine were 28, but apparently they're nearer 29 - mine's a European-built
bike, stepover thing with a modern sort of thick-tube U-shape. (Basically a town bike but with front suspension - great for crappy-surfaced Glasgow roads - & our usual sort of gears for our usual sorts of hills. (Kenda tyres, middle bit with road-chevron type pattern, knobblier at the very edge)
Bigger wheels - it does make for a really enjoyable, smooth ride. Since it's my first bike I don't have much to compare it with for nippiness, but I don't feel any lack of nipping. In some way I can't explain, it seems to make nipping redundant: the stateliness factor, but I don't know how that works. The nearest I can get to describing it, something everyone notices - (? to do with wheel size as well as the fact that my bike's a few pounds heavier) - momentum. It just rolls on forever when you freewheel. Kerbs and minor potholes don't disturb those big wheels - you tend to take a much more gentle, open line somehow, need to turn the wheel less.
My bike does a bit of everything: more shopping than I can literally carry (20kg) and I don't notice it in the panniers.