Leopard and HD Upgrade

I need some advice. I have a Macbook, and I plan on upgrading to Leopard upon its release. The problem is that I have lost the start up disks to my MB; I'm wondering whether I should contact Apple and ask them to send me disk replacements, or just forget about them and install Leopard. I'm not trying to correlate that I need the start up disks to install Leopard, but I am wondering it will be worth having them around after I have installed Leopard.

Also, I plan on upgrading my HD. Should I do this before or after I install Leopard. I am also not too sure about how to transfer all my apps and files from one HD to the other. Will the Migration Assistant also backup my apps?

Thanks a bunch.

I asked my friend the same thing, wondering what will happen to all those music files, picture files, and apps when I get Leopard.

Hmm, my friend, he's like an Apple genius, certified by Apple and Windows to work on computers and such says that the media on your original HD should just show up on Leopard.

I think you should probably update your HD after Leopard, just sounds smarter to me.