In this question, it is said in the most upvoted answer:
Use liquid layouts
Why this is considered a good practice ? My opinion is that it is more difficult to dezign a liquid layouts because it can vary quite a bit from one window size to another... Is the extra complexity worth it ? What i should take into account to make the choice ?
Hmm, I disagree with that. With a fixed-width layout you can create something which will be viewed the same on all browsers.
I've been in web design and development for quite a while now and there have been very few times I've ever used liquid layouts on a website.
There are some times when it can come in useful, web apps sometimes can benefit from having a liquid layout. However, the safest (in terms of design and everything working across different browsers, screens etc), best looking (in my opinion) and "standard" way to create websites is with a fixed width.
Just look around. See the websites which have a liquid layout and ask yourself why they have a liquid layout. Do they have a lot of areas of dynamic/varying text for instance? Lots of information to show? Lack of visual/graphical design? Its a very subjective area, but one which you'll have to choose between. Does your website look better fixed or liquid? Do you want people with huge monitors (like me - 27" imac) to have to see your website really fat? I hate viewing amazon on my mac!