Really, I don't see all that much advantage in running 64 bit. A little extra speed, but it can't run some stuff. What's the advantage?
All I've found unable to run for myself have been (1) an ancient version of The Print Shop, which was a one-time thing, to export some graphics from an old project (XP mode did the trick) and (2) some old game installers. The games usually have work-arounds, or are cheap enough every day at GoG or Steam to just buy them again. Outside of that, it has mostly been embedded devices with web interfaces that rely on IE, a couple of which won't work in 7 or 8 at all, 32-bit or no. The rest I know of is all old programs still used because the users are used to them, more than anything else (like an old label maker that does nothing Word or LOo can't do, or old photo editing programs).
The stuff that won't run is all very old, and some of it won't work in a new 32-bit Windows, either, if it relies on other programs, like IE, or old versions of DirectX. XP Mode is generally the easiest way to handle it, IME.
Meanwhile, there's no way I could by in 32-bit. VMs take RAM, Chrome takes RAM, games take RAM,
everything takes RAM, and usually in 1-4GB amounts. I've got about 5 times the RAM 32-bit can typically see, and can put over half of it to use already. I moved to 64-bit in '07, and haven't looked back.
With bloated Office, even regular users are needing more, maxing out their 2, 3, and 4GBs with IE, Word, Excel, and Outlook; then complaining about freezing, crashing, and slowdowns.
32-bit client OSes will be available, and used, for awhile yet. But, they are already rare for new PCs, and their installation base and use will only dwindle, over time. If you only have a single program open at once that can use a fair amount of memory, or use a fair amount of cache, then you won't need 64-bit unless 32-bit stops being supported.