Having said all of that, please note that stuff like NetworkManager is completly safe to remove -- why these things are in there I simply don't get.They are mildly relevant if you develop something against them, but even then I would prefer having a pure 32 bit machine to test things on.
Support libraries can come in handy however, especially if you have games with no source available that are compiled for 32 bit x86 or if the bloddy thing simply won't compile on 64 bit (it does happen -- more often than you'd think).
If you want a pure 64 bit system you can get some (meaning not everything works, and a lot of stuff is broken) flash support. swfdec has a 64 bit plugin for firefox, which is available now. It's suppoed to be able to handle youtube, but I've never been able to get that working.
I am not a lawyer.
Fedora: AMD Phenom II 905e @ 4x2500 MHz, Raspberry Pi B 512 MB @ 1x800 MHz, Raspberry Pi B 256 MB @ 1x700 MHz
Debian: BeagleBoard xM @ 1x1000 MHz, Apple PowerMac G5 @ 2x1800 MHZ