I use 64-bit TC for my internet facing servers, but then I'm maintaining almost all of the extensions I use so I know they're up to date. They take a pounding; I have the iptables syslogs saved to a postgresql database to prove it. 32-bit extensions don't seem to be as maticulously maintained, so it's probably best to use it only for personal/hobby systems.
But I have to ask: I have more than a few 32 bit systems that I paid a lot for, and I get the idea of not wanting to junk something that still works, but new 64-bit systems are fairly cheap and use a lot less electricity. Given the compute power to power consumed ratio, is it really worth keeping our old 32-bit systems lit up?