After using subversion from terminal for a while now, i've found following command so useful, I've turned it into an alias.

Add new files ready to commit

svn st | grep "^?" | awk '{print $2}' | xargs svn add

This command is a mouthful but saves you from adding each file individually.

When you want to use this alias you'll have to take care of the nested quotes and escape them.

alias sa='svn st | grep "^?" | awk '\''{print $2}'\'' | xargs svn add'

One could make several variations on this alias for svn remove, revert or others. You'll just have to change the grep and xargs arguments.