I've been using a Canon MP500 all in one for 2 - 3 years now and I love it. I loved it even more when I found a source of excellent, reliable compatible cartridges. At Canon prices it was over £50 to reload, but just £10 from my source on Ebay. Check it out here if you use Canon, Epson or Brother or need other printer consumables.
When an error code came up in the middle of a printing job I was devastated, particularly after doing an internet search and seeing thousands of other people had experienced this particular error code and the only solution was to call out a Canon engineer.
After some thought we decided that a replacement would be cheaper than a call out and repair and picked up an Epson SX415 from Currys - having established in advance that my ebay supplier had a full set of cartridges for £9.50 rather than Epson's £27.90 price tag.
When moving the Canon to make space for the shiny new Epson I jokingly said to Paul, "It wants turning upside down, giving a good shake and then dropping, and that might make it work again". I really was joking. Anyway, that's exactly what Paul did, although the dropping was a genuine accident.
Hey Presto! The Canon started working again. Not soon enough to take the Epson back to Currys as it was already installed and working.
Moral - if any Canon owners get the dreaded Error Code 6A00, try the above before throwing the towel in and getting new one.