Back in 3.5 I made two character sheets. One was for the purpose of being printed out and used. One was for use on the computer. I made the printable one in paint (yes, I'm crazy) and the other one in excel. The excel character sheet had multiple tabs organized very well over time, along with auto-calculating everything from power points, to multiclassed BAB to penalties due to negative levels.
In 4e, I haven't found a need to make one on a computer yet, but I do have one that I made printable. I also made it in paint. Both of the printable ones were converted to pdf.
I've never met anyone else who uses paint like I do, but I played with it a ton as a kid. I'm more comfortable using it than the multiple layers of a more advanced program. In fact, I haven't ever figured out how to change just a few pixels on a specific layer of a more advanced program. I guess if I knew how to do that I'd be able to use them, but the essentials that paint does so well for me, are lost on me in other photo programs such as adobe photoshop.
I've uploaded the 4e character sheet I made as example of what I made in paint through extracting images from other things. Shado's character sheet was a source of a lot of the art or my sheet, as shado extracted the art from the PHB somehow. Like I said though, I'm crazy. I wouldn't recommend paint, it just happens to be the thing I know how to use the best.