I'd be inclined to agree. I've been on Vista x64, and the biggest issues I've run across
1) Creative's drivers are not up to par with their XP drivers
2) Slightly slower bottom line performance in gaming and other intensive applications
3) No iPhone compatibility (I had to setup XP in a virtual machine to get my iPhone activated (!))
Thats about it. I haven't had any trouble getting applications to run on x64, even specific stuff like virus scanners, cd imaging and burning software, etc...
- It requires that all device drivers be designed specifically for 64-bit and be signed.
True that drivers must be designed for 64 bit, but you can bypass mandatory driver signing if you need to. That's a very good thing!
The overall fluidity of Vista is very pleasing - provided you've got a strong CPU and lots of RAM (which you do). The performance difference is present, but negligible and very much worth the benefits in most cases IMO.
The DX10 issue is complicated. There's not much point still, with hardware mostly incapable of acceptably running DX10 - but that will change over the course of the next year.
The way I see it, you're better off making the switch, now that most of the issues with Vista have been addressed. We're all going to want it when DX10 is mainstream in a year or so - thus, it's to our benefit to get comfortable with the OS as soon as possible. I know from my perspective as an IT worker, it's worthwhile knowing Vista so you can support end users who had it reinstalled on their computers.
As an added bonus, the few 64 bit applications out there are indeed faster. Also, having access to the extra RAM makes virtualization very easy. Imagine running VMWare with multiple virtual machines on a quad core processor and 8 gigs of ram. No problem
~MiSfit