I've used base 32 pretty often when I've wanted to encode numbers in an ASCII string that a user could easily enter and wanted to be sure there'd be no confusion between O (letter) and 0 (number) and l (letter) and 1 (number). So I ended up using A-Z (less the letters O and L) and the numbers 2-9. Voila, base 32.

Regards,
Craig Steiner