The web is a flexible medium
I had been mumbling around this topic, trying to explain it to myself in a way I could write it here and let you know what I have learnt about css and web design, but I have found this great article: CSS Is not Hard - If you recognise for what is it, via 456 Berea Street's Flexibility makes working with CSS easier.
This expresses exactly the feeling I had about web design: If you try to make it look exactly the same in all browsers, you're dead, dude. You know the usual issues: it looks nice and cool in safari and firefox (or camino) but you need to make lots of tricks for it to look the same in internet explorer because its standards support is, being polite, poor. But by doing that you dirty the code, add non-semantic content (presentational) to the page. And then you've lost the whole point.
We need to be flexible, accept the differences between rendering devices and enjoy them. As the article points, it's stupid to create a web for Internet Explorer 6.0 on Windows XP2 with a screen size of 1024x768 and full window with the font setting to medium. Leaving apart the fact that not everybody uses that operating system, and even in that hypothetic case, not everybody has that resolution or even a maximized window, we need to think about this recent myriad of internet capable devices. First example which comes to my mind is the PSP browser. And that's just the beginning: pda's, mobile phones...
I personally love to see how my page changes the appearance depending on each browser. I really have reached a point in which I don't mind at all if it looks weird with internet explorer. I am not going to lose any second of my life to fix that for my personal web. And well, I won't propose everybody to get such a radical approach but would suggest to start trying to pay less attention to the "rendering equalness" and more to a good content which is easy to present in every device.
Which is the goal of the world wide web, by the way.