Well below is the microsofts version of the Comparison between IE8, Firefox 3.0 and Google Chrome.
More can be read at: http://www.microsoft.com/windows/internet-explorer/get-the-facts/browser-comparison.aspx
Lets evaluate each point one by one : i would concentrate mostly on – IE8 vS firefox as I use both of them on My machine. havent played with new Chrome much so cant comment on it as of now.
As far as security and privacy are concerned , I m not a security Expert so wont be able to put a technical comment on this, But going by what had happened recently with IE7 i m little reluctant to completely believe on microsoft with Security. Also there hasn’t been any clear cut comparison of security features in IE8 Vs FireFox3.0 and Chrome .
Few Links to read about Security on both browsers :
Reading all those articles all i can say is that IE8 is better in security than IE7 and IE6, If you want to continue with IE then only go with IE8 and not the prior versions.
I have even added one alert message on my blog which will be displayed to you if you are using iE versions less than IE8.
Ease of Use: Well in todays world no software is as easy to work with, the basic operations in all browsers for a lay man are more or less same. But where firefox scores is in the advanced features for power surfers like me firefox has way to many options to satisfy our lust for surfing. good options to organise and best part is all addons are very straight forward and easy to enable disable or remove. where as in IE 8 managing addons can be quite a complex task. So for me Fire Fox scores on Ease of Use.
Reliability: Have experienced many crashes with both IE8 and Firefox but Firefox has always restored my session without any fail. have heard of a latest patch in IE8 for crashes. hope this will improve reliability of IE8 more.
Compatibility: That chart above says IE 8 is compatible. lolz. the only way i found to install IE8 on Linux wa son Virtual machine or Wine, both of them are big pains at least as far as i m concerned. where as firefox can be ported on any linux and windows and also provides flexibility to sync with all most all other browsers and online services.
Performance: I agree on that for both IE8 and Firefox 3.0, If you wnat to judge them on speed , you need a slow motion video. No comparison possible on that factor as of now.