I definitely do not recommend uninstalling Internet Explorer. Just leave it disabled (turned off) in Windows Features. In terms of security, IE9 is more secure than IE8 using the default settings for both. Just as an example, back in June 2011 Microsoft released one of its Cumulative Security Updates for Internet Explorer. IE8 required 12 patches while IE9 required only 7. And for the most part, this is pretty standard for every IE cumulative update. Microsoft Security Bulletin MS11-050 - Critical : Cumulative Security Update for Internet Explorer (2530548)
It could be argued that once IE8 is patched it's just as secure as IE9. But if it has more vulnerabilities that need
to be patched in the first place, it poses a greater security risk until it is patched. To me, having IE8 on my machine just leaves more openings for the bad guys to expolit. I use Opera as my default browser. I have IE9 installed but turned off in Windows Features. I have had no stability issues with my computer and I believe this is the way to go. When IE10 is released to the general public I plan on upgrading to it. But I also respect the old saying, "If it ain't broke, don't fix it." If you're happy with having IE8 on your machine and if your machine is working for you ...
Just bear in mind that you might be at greater risk for security issues. So make sure your anti-virus suite is always up to date with the latest data base. And it wouldn't hurt to have a couple of free
on-demand scanners available just to double-check your computer every so often. Some of the recommended products are: Malwarebytes ESET Online Scanner SuperAntispyware HitmanPro