The networking on Leopard is flawed. I work at the IT department for a small university. We, along with many close by colleges and universities, are having trouble with Leopard dropping network connections (both wireless and wired). It will work great until you turn off the computer or let it go into sleep mode. We had 3 Apple Engineers come to our campus last week and more or less said "Oh Crap" and said the problems will need to be addressed in future updates. Check Apple forums, this problem is being complained about all over. The premise that "it works for me, you must just be doing something wrong" is really flawed. Also, I myself have experience multiple crashes while using Leopard on multiple different computers.