The first posts about using 64-bit ubuntu that I can find on this forum are from october 2004. I switched to 64-bit OS myself not too long after that, and have been running nothing but 64-bit ever since both on linux and windows. Sure, there has been a few issues on the linux side with some apps not installing "out-of-the-box". But it has always been possible to make things work.
So here we are 5 years (!) later, and 64-bit is still something that people say "I might try it out". Why is that? I would say one of the reasons is this very forum section. The 64-bit version is not treated as the standard installation, so people go with the 32-bit version since they feel it is recommended. Well, IMO, that is a stupid recommendation.
When I started looking at linux, I was faced with a lot of threads telling me "linux is harder to get into than windows, but it is worth it". Now when linux is a lot easier to use and get used to, I am faced with "64-bit is harder to get into than 32-bit so it is NOT worth it". What?
I demand this section be renamed to "x86 32-bit Users" and all the other categories be standardized to 64-bit. Actually, I would have named it "legacy ubuntu", since it involves old technology. One small step for man, one giant leap for mankind.