I agree with most of what Scataphagos said. Trading is my business. I do what the business requires. No less. If the trading platform/software says "XP 32", so be it regardless whether it's buggy not buggy, feature-rich/featureless. If I use a trading software that runs only on DOS I will stay on DOS forever too. But... I need to use the computer to surf the net... I need to use the computer to play my games... or facebook this, video that... twitter, YouTube, MP3... That's where the conflicting drives come in. You want to be cool? Or you want to be able to hold your platform/software provider accountable when things fail? It's a matter of your priority.
I've put XP boxes into service this year too. And probably will next year. But I see how they run with all the patches and service packs. They just don't (and won't) run like XP did when it first came out. And I know what my benchmarks are (and performance) on 7 and there is no comparison. 7 is super fast, runs any software you put on it, uses all the ram you put on it, etc. You really should invest the time to set you up a quad core 7 system, learn all the tweaks, etc. I did it just for fun and fell in love with it. And nobody hates Microsoft more than me; mostly for hiding the File commands in Office 2007 behind a stupid fucking yellow fluffy button. Some advice to anyone who wants to play with 7 - run the diagnostic for 7 available from Microsoft and then go looking around for 7 drivers for your hardware just to make sure the hardware manuf's are up to speed which 99% are. With respect to toys, bells, whistles I have all that shit shut down/ removed. There are no toys on any of my systems; not even speakers. Looking at one of my 7 systems you would not know it's not an XP system unless you go messing around in the control panel.
In my trading room I have Win7, Vista and XP all 3. I certainly don't hate Win7 - except the Aero Peek stuff, which I turned off. I do like it that it recognizes all 6GB of my RAM. And I bought Win7 64 for that reason. But they are not all the different to me. I use a box for the trading application. I buy Windows OS for the box or for the application. The OS features don't entice me be it Windows or Linux. I only buy a box for doing what I want it to do: let me trade.
Windows 7 pro will run XP applications including IB and Ninja Trader. I do currently have to run in 32 bit mode for Ninja Trader until they work with ZenFire to make 64 bit compatible mode, however, running NT 7 on Windows 7 is faster than running 6.5 on XP, this includes load times, and number of charts that you are now able to run concurrently.