Aside from any factual weirdness about applications caring about the width of the bus itself... This is incorrect.
A 64bit OS is only good if the software (application) takes advantage of the 64bit bus.
The OS can access more memory and handle it faster, even if one app can't [PAE blows]. The OS and select apps can do more things at the same time, even if one app can't. Microsoft even claim it's more secure.
Because it runs just fine on 64-bit? Why do they need to build two binaries right now when one works fine? Sooner or later it'll stop working; as I said, half of windows 7 installs globally right now are 64-bit. Nullsoft are faced with the question; either get their stuff working, or take an immediate cut in potential customers by fifty percent.
64bit OS has been around for more than 5 years now, and winamp has yet to release a 64 bit version of their popular player. Why? For such a popular player, I don't know why.
And you know what? If they don't support it, get another mp3 player. There are lots out there.
No. How many people build 16-bit windows software nowadays? How many people release universal binaries for OSX, let alone PPC-specific ones?
Even though we see a lot of 64bit application coming out now, the 32bit version will always be available.
Admittedly there's a question of timing, but sooner or later people will be looking at 128 bit machines as rinkydink and the holdouts will be saying "Even though we see a lot of 256bit applications coming out right now, the 128bit version will always be available".
Exactly. You know how right now, everyone kvetches how IE6 is some kind of terrible thing that we all need to stop using, yet people are still using it?
But it's kind of a chicken/egg thing. Running everything on emulation is a disadvantage, but without high enough demand there won't be any pressure to make the switch.
This 32-to-64 bit thing is the same; at some point, there'll still be people using it because software they use targets it, which only targets it because they use it.
At this point, what everyone *should* do, but of course won't, is go 64-bit on their next install. Any applications that don't work, you submit bugs and stop using. Xport, for example; as already stated, gpsgate replaces it.
In the end, Joel covered this better than I could: http://www.joelonsoftware.com/items/2008/03/17.html. I fall firmly on the idealist side, which I feel I can afford to because I'm a software developer and a long term Linux user, from back when Linux sucked; through copious amounts of personal experience, I can confidently state that
1) Getting my code running on 64 bit has never been a problem. Developers who find it's a problem shouldn't be allowed near a compiler.
2) I can get along fine without piece_of_software_X if the developer doesn't want me to use his stuff. There are always replacements