An Epson XP-830. Full disclosure: When it was brand new it was a severe pain in the ass because it wasn't supported by CUPS yet, I had to go out to Epson's website and download a driver in .rpm fromat and install it with alien. Bought it a couple months before I abandoned Windows for Linux and had to make it work. After about a year CUPS suddenly knew what to do with it and it's Just Worked(tm) ever since.