We have been very pleased with our Pixma ip8500 printer, which we have been using for A4 prints over the last few years. That model is no longer available, but the current Pixma iP4700
looks to be good.
Here is a more recent Canon Pixma all-in-one printer: the MP610 which is what we are now using as an everyday printer in our office.
For an A3 printer, we suggest the Epson Stylus Photo R2880

For larger prints, we use an Epson Stylus Pro 3800 A2+