Here are some tricks to help those running off the trunk. Here's a useful bash script I wrote to svn update everything but the wp-content folder. svn won't work sometimes if you delete the default themes or svn files, so this script comes in handy as a quick updater. Bash scripts can only be ran from shell, google if you don't know how to use them.
Also, heres some .htaccess code to prevent prying eyes looking at the .svn files.
<Files ~ "^.svn">
Order allow,deny
Deny from all
Satisfy All
</Files>