does it really matter if your code is 'valid' or not - i have checked loads of sites recently and hardly any of them are....what's the point?

It is related to the way content appears in different browsers (that parse wrong code differently) and some search engine crawlers like valid pages more than invalid ones.

Depending on the errors, the error could be nothing serious or potentially liable. As rob said it can help make sure the site is cross browser compatible, but it also helps making sure your site is accessible. Can blind people use it?

General rule of thumb - if it looks good and your content can be read on most OS and browser then thats all that really matters. Unless your claiming to be able to build perfectly coded websites! - Then validation does matter, obviously!

It's six of one and half a dozen of the other.

 

Not even Google validates. They don't close their body and html tags because it doesn't effect their site and improves speed.

 

Matt Cutts (Google) even said himself that it wasn't really essential.

 

Personally, however, I like to make sure my code validates because it's a testiment to my knowledge of CSS and HTML.

 

Futhermore, valid code is predictable code...