Disable Windows Defender and install MSE, it is heaps good and it is free (on Windows 7). Keep Windows Defender on Windows 8 because it is just like MSE on Windows 7.
I would not with Vista over XP, heck I would use Windows 95 rather than Vista. Vista has so many bugs. Business still use XP because they know it works and when they find something that works they stick with it.
Yes, I have tried every browser there is each on different OS' some suit one OS while others don't. I use IE on Windows, Firefox on Linux and if I was using Mac I would use Safari. Each of these Internet browsers as built for that OS in my opinion. I stick clear of Google Chrome and I use Opera...
Yeah. I like it being aggressive though.
I am used to ads now because I have been using IE all my life but I just wish it had AdBlock. IE10 looks the best out of the browser on Windows 8 I reckon.