Like Martin, I choose for Canon printers, respecting of course that other people prefer other brands.
I now have an A4 (8.5 x 11 inches) i950 with six colors and I'm very happy with it. Even after two months of non-activity it hasn never let me down.

My wish for later this year is the Pixma9000.
The 9500 has even more inks and uses a different kind of ink, but, like the Epson I had, it tends to dry in the nozzles if you don't use it very regularly.
The main advantage for me is the thickness of paper you can use.
A second advantage is that you're not even limited to A3 but A3+ can be printed on it. This means:

A3+ = 329mm483mm (1319inch).

I've been to a Canon demonstration day, and although the 9500 has grey inks, the 9000 did a very impressive job when it comes to black and white prints. I could not see any coloured hue  on it. I asked for a print on a watercolour paper of 300grs and despite the lack of profile for it, the result needed fine-tuning but not more than that.

It also comes with software that integrates very well with PS.

The disadvantage: like all printers, the inks come with a price-tag...

There are no Borg. All resistance is fertile.