Which all-in-one inkjet printer is cheapest to use

Ray writes: "A year or so ago I got my dad a new computer system that included a Canon PX-160 printer/scanner/copier to replace his aging Lexmark with similar capabilities. On my next visit I asked him how the new printer was working and he said the ink was killing him. The cartridges are expensive, they don't have much ink in them and there are no third party or refilled carts for it or apparently any other Canon. It looks like HP and Lexmark are the most likely to have (relatively) inexpensive supplies but what has your experience been with inkjet all-in-ones as far as TCO goes?"