LaBella Black Nylon Model No. 15.
These strings are thicker gauge so they don't buzz in the slots at the nut. The nut is the string separator at the tuning end of the neck. The Dixie has some pretty big slots for the strings and smaller gauge strings can buzz.
The package doesn't have the string sizes, but the LaBella site does:
A - .028
E - .032
C - .040
G - .028
Maybe the black nylon has something to do with the thicker gauge. Whatever, they don't require a rubber band or other method of keeping the strings from buzzing.
These strings are less expensive than many other ukulele strings, too.
My wife has played the same set of these 5-6 days a week, several hours a day for the past three months and they are still sounding good.
Let me know if you find some other strings that work well for a Dixie. I'll do the same.
We've tried a LOT of different sets of strings, and none of them work as well as these.
Edit: 08/22/2014: As a testament to these strings, my wife has now used the same set for over a year, with no broken strings and no apparent degradation in sound. Except for the "Hillbilly Amplifier" I added (a cake pan resonator explained in an earlier post), her Dixie is not amplified, but her voice is. So, she plays the strings HARD. But note that she keeps the strings and the instrument clean of dirt and oils.
Edit: 08/22/2014: As a testament to these strings, my wife has now used the same set for over a year, with no broken strings and no apparent degradation in sound. Except for the "Hillbilly Amplifier" I added (a cake pan resonator explained in an earlier post), her Dixie is not amplified, but her voice is. So, she plays the strings HARD. But note that she keeps the strings and the instrument clean of dirt and oils.