OS X Best Practices

I recently took my office Power PC G5 into the shop to get serviced. Anyway, the tech their told me that I had too much stuff on my desktop and that I had way too many things automatically activate on start up. He said that was hurting performance.

Is there a book or thread I can read up on for other "best practices" hints for OS X?

I'm getting my new Mac Pro in about a week and want to set it up the right way for once.

Mac 101- Basic Mac info from Apple. I'm aware you're not new to Macs, but it's always nice to start at the basics, I suppose.

Depends on how much RAM you have really. The only thing that having loads of stuff on your desktop and a lot of "Open at Login" items will do is slow down the boot up time.