A short rant:
I and my clients are NOT going to withhold service packs and critical security patches for modern Windows clients (read: Windows 7 x64 SP1) just so your poorly written print drivers will install and run in a stable manner. Crashing the print spooler service leaving all installed printers unusable without a reset is not acceptable.
I'm looking at you Adobe PDF and Nova PDF . . .
Instead, we will look for compatible substitutes from your competitors. Once we change to those alternates, it's highly unlikely that we will EVER return to your products in the future.
Get it right, or lose our business!