The i550 is trying to hold out. Although you'll find it in lots of stores, its days are numbered. It is currently at a slightly inflated price level. Compared to the more recent i455, it is more economical in terms of ink consumption but the quality is not quite as good. Opting for it is only justified if you find closeouts at bargain prices. The i560, once level above and its official replacement, beats it hands down in almost every area.
This is Canon's new star. It's the fastest mass market inkjet printer hitherto produced. It holds the speed records for printing in draft mode, in black and white, and printing photos, and it only lost the color speed printing record by a whisker. The print quality is also excellent. The ink drops are 2 Pico liters in size in high resolution, and are invisible in photographs. This is one of the best, if not THE best printer of the year. Its major rivals are the 5652 deskjet, a brotherly fight to the death, the new i865.
It was the great favorite a few months ago, but it's become slightly outmoded due to the entry of the i560 and the i865. Although officially replaced, it's still available in many countries and is always one of the fastest on the market. The quality of the output rivals that of photo printers and it is very economical in terms of ink consumption. It should be added that it runs very quietly. However, it has a few defects. It has no paper analysis sensor like those used by HP and Lexmark, the colors tend to change over time if the photos are left exposed to the air and it is beginning to date.