Did you purposely turn off your Signature?
I am happily using AMD64 mobility Athlon 3000 at between 800-2000 KHz on my laptop with SUSE 10oss 64-bit and it runs 32-bit software out of the box (or in the case of Firefox 1.0.7 as downloaded as a 32-bit application) the only slight complication I have encountered is having to put Lame file(s) into /lib and /lib64 to enable XMMS with an old Winamp skin (yes, you guessed it, a Ferrari skin) to play my MP3's.
Anyway, as far as I know, there is no problem running most (legacy) 32-bit apps on a 64-bit linux OS. And as you can possibly see from my signature, I am experimenting with xen3.0 64-bit which allows concurrent running of 32-bit and 64-bit distros - so if you want to experiment with both 32-bit and 64-bit OS's on a 64-bit CPU'd hardware I would suggest AMD over Intel (at the moment) and linux over MS. The User's Guide provided with Suse10 OSS (downloadable version) is the best I have seen on setting up xensoftware and virtual machines and version 3.0 is included as are a variety of tools under YAST for installation and setup.
Hope this helps