Re: x86 family
There are 64bit extensions for x86 at the moment, commonly reffered to as x86-64, and yes they are considered part of the x86 family since they are backwords compatible with previous architectures.
AMD brands them as AMD64 and intel brands them as EM64T
Not all of their new processors at the moment are 64bit though. All Athlon64,Opteron,Turion models from AMD are 64bit compatible (semprons are not yet).
From intel the majority of Pentium 4 (5x1, 6xx and above are 64bit), I believe all the Xeons are 64bit too. The centrino (Pentium M) and recently announced Core Duo are not 64bit compatible. The same goes from Celeron (I heard about 64bit versions but am not sure if they are out yet)