Web browser memory usage

From my experience, Chrome is a bit free on the system resources, especially if you go to some heavy sites (if it can use more memory to make your navigation faster, it will).

About Firefox, the weight is usually caused by the number of plugins and toolbars you have installed. Try intalling it again in a separate place, and install only the minimum of plugins.

Opera is not the lightest, but it has reasonable memory use in my opinion (amongst other great functionalities in my opinion, but this is not the place). Also, you can't install plugins besides the included ones, it helps with not cluttering it.

Keep in mind though that websites are getting heavier and heavier. The amount of javascript, the plugins they require (like flash) make some pages really heavy. It's quite common nowadays that the browser becomes the heaviest program launched, with an average memory usage around 300-400mb.

For information, here is a recent (as of today, at least) comparative between browsers, to give an idea of the speed and memory uses you should expect.

In Chrome, use Shift+Escape to view memory usage per tab and memory usage per plugin. Hopefully that demystifies why Chrome is consuming so much for you.