I have the MP640 and am happy with it. I find it excels at printing photos. I particularly like the fact that it is a duplex printer and is wi-fi enabled so it can be sited away from the PC. It also allows you to print directly onto CD/DVD's if that is your thing.
Yes, it can work as a stand-alone copier.
I do not notice it being very heavy on ink unlike another Canon printer that has been the subject of much debate on the PCA forums. The cartridges are chipped but my local supplier can get round that when he does refills for me and compatible inks are available on-line.
If it has a downside, I find standard text printing looks a little smudged, but that may be because I am using cheap photocopy paper. Also, it is not the fastest printer that I have owned. it seems to take ages to churn out the first print, but after that it is much better. Take the stated print speeds with a large pinch of salt.
Good luck with it.