I went up to serverunleashed.com last week to have a look at Microsoft's marketing efforts for Windows Server 2008 launch.
On my freshly installed Windows Vista Business x64 with SP1 laptop, I was finding that Internet Explorer was locking up before getting to the loader progress bar (the one that appears on Vista and Server 2008 boot up).
I disabled all the add-ons (except Silverlight) to see if one of the add-ons was causing the problem. No go. My XP boxes were displaying it OK, as was my test Server 2003/2008 boxes and another Vista box.
One thing different with my laptop is that it has a Wacom Bamboo tablet. Which means that loads a heap of tablet-specific drivers and helper applications. I would find occasionally that when I launched Internet Explorer it would prompt me to run wisptis.exe, for which I always clicked Allow but never checked "Do not show me the warning for this program again". I thought this might be the problem, because when I force closed IE7 and selected "Look for a solution to this problem and restart Internet Explorer" it would restart IE and prompt to run wisptis.exe.
I went hunting for wisptis.exe and found that it's a pen input device utility that can be installed from a variety of sources, including being bundled with the OS. It's also useful in talking to the tablet digitisers, so removing it or not running it can impact on the usefulness of the tablet device.
Once I checked "Do not show me the warning for this program again" when prompted to run wisptis.exe and clicked Allow, then I was able to successfully view serverunleashed.com.
So if you're having Internet Explorer lock-ups when visiting a site and you've got tablet devices/drivers installed, this could be your problem.