I have done quite a bit of research into this, and here's what I came up with:

1. Buy Epson! - Everybody swears by their photo printers
2. You get what you pay for - There aren't too many big differences between the 780, 820, and 890, other than price. However, people say the 890 is much more sturdy and well-built than the 780, and is worth the price difference.
3. If you want to do large prints, nothing beats the 1280, which can do up to 13x44 panoramas.

Overall, I think it comes down to the 890 or the 1280. Unless money is really tight, I'd say go for the 1280. It's worth the extra money.

If you're really lucky, you can find a 1270 used or on clearance, although it's pretty rare these days. There's pretty much no difference between the 1270 and 1280.