Yes, you can be more specific.
For example:
CREATE DATABASE "scratch"
WITH OWNER "postgres"
ENCODING 'UTF8'
LC_COLLATE = 'en_US.UTF-8'
LC_CTYPE = 'en_US.UTF-8';
Also I recommend to read the following pages about locales and collations in PostgreSQL:
- http://www.postgresql.org/docs/current/interactive/locale.html
- http://www.postgresql.org/docs/current/interactive/collation.html