Numbers of bits

Last night I installed the AMD64 version of Ubuntu 9.04 onto my new computer. Tonight I'm deleting it and reinstalling the (older) 32 bit version. Basically: the Linux kernel allows you to run 32 bit software under the 64 bit system, but the Ubuntu userspace has several safeguards to prevent you from doing so. I would rather waste some CPU capacity than be unable to run the drivers for my printer, and being unable to run skype once I get the internet at my place would also be a nuisance.
I still don't have the internet at my place, but I will very soon.