On the subject of >>, actually that is bad for accessibility. (Screen readers read that out "greater-than, greater-than, which is not good.) The correct thing to do is:
1. First make sure that you have called check_theme_arrows();
2. Then use $THEME->larrow and $THEME->rarrow with $a. Instead of < and >
I think also that check_theme_arrows does the right thing when the user is using a RTL language.
You can see an example in http://cvs.moodle.org/moodle/admin/roles/assign.php?view=markup, starting from the comment '/// Print the form'. Oh dear, bad example, it is another place where we concatenate language strings that has not been fixed.
But since there are other place that get this wrong, you don't have to fix it yourself. I'll create a new bug, assigned to me, to fix all these before the Moodle 2.0 release.