To block Internet Explorer is suicide in my opinion.
I hate the browser, I think it's slow and buggy and rather rubbish at the job it's mean to do. If I could choose not to support the browser, believe me I would!
However, it is important to recognise a lot of people still use Internet Explorer, something around the 60% mark (I may be wrong on this but I know it's a massive number), and if you block access to that website you are blocking the access of 60% of the traffic on the web to your site. 9 times out of 10, these people won't even bother going back to your website on a different browser ever again.
If you are that bothered about writing code to fix IE bugs, then I would suggest you take a look at the way you actually code your HTML and CSS. It is very possible (and easy) to write HTML and CSS that will work on ALL browsers (with the exception of IE6) without using conditional tags to load IE specific fixes.
As I have mentioned IE6, I would suggest developing a very low-res version of the site to run on this browser. So instead of having a nice site that's got gradients and transparent PNG's, when some one in IE6 see's the site they will see a very basic layout with a reminder to either install Google Gears, or upgrade their browser.
You must remember that while most of the people who go on the internet do own their own computers, they may not have decent enough hardware to run a better browser OR want to upgrade their browser. A guy in the office the other day said he loved using Internet Explorer, while he could see why people may hate it, for him there was no other option to view websites. He wanted to use IE.
But it is very possible to write CSS and HTML that will look the same in Firefox and Chrome as it will in IE 7 and IE 8. I think you need to look at your coding skills and practices before cutting IE out.