I've been suffering silently with this problem for a long time. It happens on all of my machines. Granted, they're all configured almost essentially the same. IE is my default browser. When I type a URL into the addressbar (which I have on my taskbar), my system sometimes takes an awfully long time to open the browser window and load the page.
Sometimes this also happens to my explorer windows - they freeze up. I can always kill the process and restart it, but it's just odd. It hasn't plagued me enough to do much about it, but a few weeks ago, I tried to narrow down the problem by uninstalling all IE addins such as the google toolbar, but the problem still repro'd. So I gave up.
Today, a coworker suggested something after watching my system churn when opening a URL... “That looks like a GDI leak.” So I fired up the task manager, added the “GDI Objects” volumn (View | Set Columns), and noticed that wisptis.exe had thousand of objects, which probably ain't right. I killed it, and my system seems snappier... but it's hard to tell since it isn't very consistent to begin with.
I googled wisptis to find out what it is, and got to this page, which does mention the possibility of a GDI leak. So I'm going to try this for a while and see if it helps.
By the way, it strikes me as incredibly stupid to have this tablet-specific code running at all times when it's not necessarily on a tablet machine; I hope they had a good reason for that. (It's not really clear to me who “they” is in this case - Adobe? Microsoft?)
[Update 7/9: Thanks to Larry for pointing it out, there's a fix to get wisptis.exe off your system, if you don't need it. Read the comments on this post.]