I hope it hasn't been mentioned before but 64bit software support can be a bit slack also. Take for example Adobe - a company you think would have been STRAIGHT onto the 64bit bandwagon!
While we have had 64bit Photoshop (and 64bit Photoshop extentions, which I think showed up for PS CS2? Or was it later) for YEARS, we still do not have a 64bit Flash browser plug-in. As pathetic as it sounds, because of Adobe, I need a 32bit browser installer, so I can order pizza over the net or use a few shopping sites that use flash! We've been told for YEARS that a 64bit browser plug-in is being developed and still nothing besides a x64 Prelease last month!
While on the topic of FireFox, hey look, NO 64Bit version (except for an independant? x64 port that is always a few months behind the 'official' releases) and none planned until at least FF4.0!
Then we look at the REST of the Adobe Creative Suite (of which I am a regular user); as of CS5 (which many larger organisations haven't rolled out yet; I'm still on CS4 even though i have a CS5 box sitting on my shelves) only Photoshop Extended, Lightroom, After Effects and Premiere Pro (including Media Encoder) are 64bit apps - essentially only the video production tools. Everything else, like Illustrator, Dreamweaver, Fireworks, Acrobat Pro, etc are still 32bit apps - while these are the apps that typically don't need as much GRUNT as the aforementioned, I am disappointed that Adobe continues to roll out 32bit software.
Still, the big issue is Flash!