I puchased Vista Ultimate the day it came out (I am one of those early adopters of technology) and installed in on my desktop, which had the fastest CPU going at the time and the fast GPU, the AMD FX-60 and the Nvidia 7950 GX2 1gb, and since then I have never had a bad moment with Vista with one major exception.
I would highly suggest that you change the default rules with alllows windows to upgrade your computer at will with all upgrades that come out whenever they come out and change it the the option that Vista should not download anything but simply alert you that updates, security patches and the like are available and give you the opportunity to review and study them decide which you really need. As the old adage goes, if it ain't broke, don't fix it.
I have only had major probelms with Vista twice and both involved my own negligence were I forgot to change the setting discussed above on one of my son's computers and their dedicated "Flight Similulator" computer. In both cases downloads from Micorsoft got stuck in Stage 3, Installing, and would stay at 0% for five mintutes, restart the machine and do it all over again. I tried everything but simply made matters wrose and in the long run I had to reinstall Vista on both machines. The problem you will find is that while many of the updates are necessary security patches a whole lot of them, when minimal ivestigation is undertaken, are solely designed for work enviroments with networked computers and IT guys using various tools provided to get into users machines to diagnose problems etc.
Antoher annoyance is that Vista will continue to want you to download laguage packs in languages most of will never even hear, much less use, unless we visit the Congo of restricted areas of red China regularly. I mean gigabytes of this trash.
My lastest mishap occured just a few weeks ago as it turns out my son who is home from college and has built high end desktops with me as a hobby for a long time, accidently turned automatic updating back on on his laptop; one of those things that happen at 3am. The next day the computer was trying its level best to install three updates it had downladed from Microsoft but my guess is that they likely could not be installed due to the lack of some prior update. Catch 22, however, was that the problem completely kept out of the system and all restore points disappeared when Restore was accessed from the original Vista Disk. somehow would not show up when I tried a repair with the original VIsta Ultimate Disk. To mske a long story short, which obviously I have trouble doing, this has happened twice and both times I have had to re-install Vista which also leads me to suggest you look into the My Book Home Edition from Western Digital if you do not have a backup drive running backup software. I have them installed all over the house, literally on laptops and desktops; actually I should install a server. Back to the subject, do some reading on the My Book and you will find that its software, available in the home edition but beware the Essential edition, acutally saves to the backup as you save to your hard drive. At least this is how I read the box and reviews. I am not suggesting this due to Vista as I had more BSOD with XP Pro then I have ever had with Vista. While Vista has gotten a bad rap is is in some ways unfair as with the correct hardware it it tremendous. Unfortunatly no one told most of the country looking at changing OS's that htey would likely have to double their hardware investment if they wanted to utilize Vista in the same easy, non-opbstusive way they were used to using XP. Luckily your system has more then enough hardware to make using Vista an enjoyable experience actually allowing you to accomplish more instead of being a burden keeping you from getting needed work accomplished. As for speed, with Vista I consistantly, depending on how I have tweaked my system, get 3dMark06 socres of 17,000 plus. A last tip, keep your graphics dirvers current as this makes a big differnce sometimes under Vista. Best of luck to you and I apologize for rambling. I will work on my brevity. I write briefs mostly for a living and actually have a hard time keeping things short, so I apologize to everyone in advance and will work on my problem. Either way I know I will get some rude comments but such is life.
Computer
Home Built
Thermaltake Tusami Case
Gigabyte GA-EX38-DQ6
Quad Core Extreme QX6850 Overclocked (waste of money as no program I use or that even comes to minds can recognize four cores)
Asus Radeon HD 3870 X2 1gb (currently looking for a second to crossfire with)
Coolit Freezone Refrigerated Water Cooling with 6 Thermal-Electric Coolers (TEC) or Peltiers to chill the water prior to recirculation / CPU kept at constant 30c, case interior 33c.
Patriot Viper 4GB 1066 (PC2 8500) Memory
1,000 watt modular PSU
Latest 3dMark06 17,274, with simple multiplier overclocking