IE7 (RC1) might cause you problems …
Currently I have IE7 Beta3 running on my desktop and I nearly pushed the button to upgrade but then I checked the IEBlog comments and right now there seems to be a lot of negative issues regarding the upgrade. So personally I am not making this leap, maybe Release Candidate 2?
The browser I personally prefer is Firefox 1.5 which is small, stable and fast with a great range of add-ins but more importantly for me, it has the best web standards support right now. David Hammond has compiled this awesome interactive browser standards comparision table showing which browser supports which standards.
Don’t get me wrong there are features of IE7 I would like Firefox and other browsers to adopt from Microsoft. i.e Simple List Extentions (SLE) and two other forthcoming technologies LiveClipboard and Simple Sharing Extensions (SSE). These three technologies I think will fundamentally change the way we all (re)use data on the web, just as Cut & Paste did for desktop aplications when it first appeared in Microsoft Office.