I have a Canon Powershot G2 which I bought about 3 years ago. I download using Canon's Zoombrowser - it's not a speedy process, but I put that down to the size of the images to be downloaded [I don't know a huge amount about the subject!]. I recently bought a 1Gb CF card and was staggered to find that I have the capacity to take over 800 shots at the best resolution, and 7500 [yes, 7500] at lowest!
I guess to optimise performance you need to download all the manufacturers 'fixes' and 'updates'. That probably means changing hardware as well. It depends on whether you can justify the cost against the increased performance...