Ok. Just what the hell are you talking about? Can you call Vista a huge improvement? Can you call Office 2007 a huge improvement? Visual Studio 2008 a huge improvement? These are the most problematic piece of software Microsoft has ever made since at least 2000! Sorry but it looks like you are looking at the "Improvement Graph" backwards.Tiger is the only thing you need to consider here. Since 2005 Microsoft have made HUGE improvements to their software.
Complete BS. OS X is more stable then ever. Maybe you're confusing Leopard with Vista and Tiger with Xp?Since 2005 Apple have gone in completely the opposite direction, taking their OS from the pinnacle of speed and stability to the point where program hangs, crashes and kernel panics are much more common.
You only need to use Windows 7 for a few minutes to realise just how much faster it is than Leopard. You can launch software and it's running instantly, whereas on Leopard you'd be staring at the icon bouncing in the dock.
BS again. Leopard is FASTER than Windows 7. While the icon in Leopard bounces on the dock, the application hasn't even appeared yet on Windows 7. You're perhaps comparing a fresh/not very used Windows installation with a quite used Leopard one, like uberamd said. For that matter, my Windows 7 in my 35 GB Boot Camp partition is much faster than Leopard. Why? Because the only thing installed is a damn game. Try actually using Windows 7 as much as you use Leopard, and come and say that it's faster. That's pure BS.
Windows 7 has never got any chance to be as fast as Leopard (not even speaking about snow leopard) as long as it has the registry. The registry just keeps growing and you cannot stop it without risking to delete something important aka causing corruption. Not to mention the still not-well-functioning memory caching.
Windows in general may "FEEL" faster than Leopard in some cases because of the minor Visual effects (Such as minimizing) and it certainly IS faster if it's got very little programs installed. But otherwise, there's simply no contest.