howto choose the right character set in MariaDB
Choosing character set usually based on the environment, each set has pros and cons. for example if your system has mixed character I strongly recommend utf8 but even utf8 has many types. for example: utf8_general_ci is faster than utf8_unicode_ci but less accurate for sorting. and if you want to use specific language Czech for example then you need to make the character set utf8_czech_ci to get full language function.

I found the following URLs regarding encoding hope they will help:
http://dev.mysql.com/doc/refman/5.0/en/charset-charsets.html
http://dev.mysql.com/doc/refman/5.0/en/charset-unicode-sets.html
http://code.openark.org/blog/mysql/mysqls-character-sets-and-collations-demystified

the following URL contains some examples about disk usage for character set:

http://spin.atomicobject.com/2010/08/23/on-the-importance-of-character-sets-and-character-encodings-in-mysql/