This closeup portrait of my daughter was taken with a very sharp lens -- the Canon 100 f/2.8 Macro -- on the 8 MP Canon 30D. I used a tripod and shot at f/11 to ensure maximum sharpness, and used ISO 400 to enable a shutter speed that would minimize subject movement issues but at the same time would not be overly "noisy" (you can still see a bit, but it's not troublesome).

Not that at 100% viewing, there is still crisp detail around the eyes (because I shot from up close, even at f/11, there is a bit of softness farther from the "plane of focus"). This picture is, to me, suitable print at a reasonably large size, because I did what I could to "squeeze the most" out of my gear.