Wow. I just installed it, and I've found two problems already.
Firstly: I like using the keyboard alot, so I use alot of the ALT + [letter] shortcuts. One thing that annoys me is, if you press ALT + F, you get the normal File menu, right? Then I noticed there is a Tools menu as well, so I thought I'd try ALT + T for tools (which it is supposed to be, because the T is underlined) and the Tools on the right side opens up. Come on, Microsoft, I thought you guys would have learnt from your first mistake, which you still haven't fixed yet (in the "non-classic" start menu, Open up start, and then press P for Programs to open up, and it only highlights programs, because there is a "Printers and faxes" shortcut there which uses the letter P as well. I have the classic start menu, but I'm just trying to make a point here).
Also, how would you open up Tools, without using the keyboard?
Now, secondly: I have always loved Firefox for doing this: If you type in [in Firefox] in the address bar: "anandtech off topic" for example (without the quotes) then it'll take you straight to Anandtech's Off Topic (i.e: the first page in the Google search). But Microsoft has decided to keep redirecting you to their MSN Search page: why?
But then again, Firefox has this original feature (as well as (in the latest version) typing "wp anandtech" it should take you directly to the Wikipedia article on AnandTech). But I guess that's what diffrentiates the programs (even Opera doesn't have this feature)
EDIT: forgot to mention that Internet Explorer doesn't render some pages properly. Go to Wikipedia (as an example) and try opening any article: you'll notice their logo on the top left will have disappeared (if you don't believe me, try opening the same page in Firefox, or what ever else you have (I've tried it on Opera, and Firefox, and the both show it, don't know about Internet Explorer 6, but Internet Explorer 7 definitely doesn't show it)
EDIT: Also forgot to mention my first looks: overall, pretty nice GUI, but could use an improvement in some areas: e.g.: the Tools menu. Also, what about beginners of the Internet? I'm pretty sure they'll find this browser pretty confusing because of the way everything is hidden. I mean my mother (who is unfortunately an computer illiterate) has just gotten used to using Internet Explorer 6, then I switched her over to Firefox, but she quickly set it, because it was much simpler (she pretty much just points and clicks at hyperlinks) but the best part of it was just entering websites withouth www and com. I wonder what she will think of Internet Explorer 7.