I've been using Win 7 for months. It's fast and MUCH better than Vista. They don't talk about it much, but a lot of this is because Microsoft re-engineered the video subsystem.
A large number of crashes in Vista were because of the single-threaded video system and making a dual copy of video memory. With Vista, if you opened a large number of windows and especially if you have multiple monitors, Vista's video sub-system would keep chewing up memory until it crashed. Also, all communication with the windows went through ONE portal. Basically, it was a horrible design.
In Win 7, the video sub-system is multi-threaded and it keeps a single copy of window memory. You can keep opening windows and not use up much memory. I've had virtually no problems with Win7. In fact the Win 7 beta that was available last January was far more stable than the production Vista OS after years of patches.
Another thing to consider is 64 bit processing. 64-bit processing with Vista was questionable - mostly drivers were not available or didn't work well. With Win7, 64-bit is a production-level reality.
The big advantage of 64-bit is the ability to use more than about 3.2Gb of memory. Big apps like photo and video editors work more smoothly. My office workstation has 8Gb of memory. It's normal for me to have 8-12 windows open with software development and office tools, a browser running video (YouTube), a couple of resource-intensive chat windows, AND database software running simultaneously. Sometimes my system uses over 6Gb of memory. This would not be possible on a 32 bit system. On my 64-bit system, it runs smoothly.
All of my home systems have been running Win XP for years. I wouldn't buy Vista under any conditions. However, I just bought upgrade licenses for all of my home 'puters. Win 7 is the best thing that Microsoft has produced in years.
Regards,
Dan.