Dont know if anyone plans to use w7 64 bits and use firefox..but...just to let know that you will not be able to use java on firefox out of the box...
you need to download java 64 and 32 ant then do a small trick to make it work...

here
Obelisk: How to: Java in Firefox 3 on 64-bit Windows 7 or Vista

good luck!

(same thing applies to vista 64)