The bad news is that advanced, printer-specific features (e.g., an advanced stapling/collating system) won't be available with a generic driver, but getting back a basic level of functionality is often worth the tradeoff.
The worst case is when you encounter a printer that uses a proprietary wire protocol and doesn't speak PostScript or PCL. Inkjet printers are infamous for this sort of thing, but some laser printers also suffer from it. Case in point: my own HP LaserJet 1000, which uses the proprietary Zenographics protocol, does not speak PCL, and has no 64-bit drivers whatsoever.
If I wanted it to work, I had to hack a solution together, or simply install the printer on a 32-bit instance of Windows and open any documents to be printed there.
Another workaround: I set up a print-to-.PDF driver on my 64-bit machines, and had the results printed by default into a shared directory that the 32-bit machine would poll periodically for new documents. Yet another solution involves simply printing to .PDF on the local machine, and then invoking an XP Mode instance of Acrobat Reader to print it to the actual device.
All workable, but horribly convoluted. My long-term plans now involve buying a printer that speaks at least PCL6, and never touching anything with a proprietary wire protocol again.
Scanners are another class of hardware that seem to be hit particularly hard by the 32/64-bit changeover. Like printers, they tend to remain in use for a long time. I've seen scanners five and ten years old still delivering acceptable results, with the only incentive to replace them coming in the form of a newer OS that doesn't have proper driver support.
Many scanners not more than four years old have no 64-bit support and probably never will, because all official manufacturer support for those devices has been discontinued.
Leave it to an entrepreneur to step in where others have walked out. Programmer and former NASA/JPL staffer Ed Hamrick felt he could put new life back into old canners that had no reason to end up in a recycle bin, his own included.
To that end he wrote VueScan, a program for both 32- and 64-bit Windows that works with a staggering variety of scanners. It doesn't depend on the manufacturer's drivers to do this; instead, Ed wrote his own generic device driver, and constantly adds support for new scanners as he goes along.
Server Market SplitsvilleJust because the server market's in the doldrums doesn't mean innovation has ceased. Far from it -- server technology is enjoying the biggest renaissance since the dawn of x86 systems. But the primary driver is now service providers, not enterprises.