if the OP was shooting RAW and doing no PP then the images would be quite soft, as the camera applies no sharpening in RAW mode. In jpeg mode the camera will apply processing according to the camera settings, but does not do this with RAW. so if you are shooting RAW files you need to sharpen them on the computer in post processing.
My canon 40D will produce quite sharp jpegs, but the RAW files require sharpening to make them look nice.
having owned a canon 50mm f1.8 and used it quite a lot, i think the OPs photos were not taken with one of those as it is a very sharp lens.
Peter,
in photoshop (I use PSE6) the two things you want to play with for sharpening(on jpg files or RAW files you have converted to jpeg) are the unsharp mask tool and the high pass filter.
USM is found in ‘enhance’ > ‘unsharp mask’
HPF is in ‘filter’ > ‘other’ high pass. however you need to use a new layer and change the blending mode to ‘overlay’ before applying the HPF to the new layer.
google for tutorials on both methods. there are a few out there that explain it well.
if you dont use RAW already it is worth a go, but is more time consuming thatn jpg format