I have to warn you that putting a lot (over 50) redirections in the .htaccess file causes observable performance loss. The .htaccess file is read to memory, parsed and executed for each and every request sent to the browser, even for static files like CSS, Javascript, images, videos, etc. A typical page contains around 30 such items. If the redirects cause a 0.05 second delay, then the whole thing adds up 0.05 * 30 = 1.5 seconds to the page load time. The slower the server, the busiest the site, the more the static files and the more redirections you have, the worse the problem gets.
I would strongly recommend using either Admin Tools Professional's URL redirection feature, or Joomla! 1.6/1.7's Redirection core component to implement the redirections. This way, the redirections are only parsed for the HTML content, not for static resources. If you have over 50 redirections, using this kind of redirections gives you a measurable speed boost. Believe me, I have 400 redirections set up on this site and I know what the impact is ;)
Nicholas K. Dionysopoulos
Lead Developer and Director
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