I thought it was interesting to see that some people actually tested the length of URLs in different browsers. You have to know that the size of a URL in the location bar may be differently limited than the length of the URLs you can go to with the browser (i.e. the URL in an anchor may need to be shorter! Or could be longer and still work.)

Note: These are Browsers limits in 2006.

Microsoft Internet Explorer

Microsoft states that the maximum length of a URL in Internet Explorer is 2,083 characters, with no more than 2,048 characters in the path portion of the URL. In my tests, attempts to use URLs longer than this produced a clear error message in Internet Explorer.

Firefox

After 65,536 characters, the location bar no longer displays the URL in Windows Firefox 1.5.x. However, longer URLs will work. I stopped testing after 100,000 characters.

Safari

At least 80,000 characters will work. I stopped testing after 80,000 characters.

Opera

At least 190,000 characters will work. I stopped testing after 190,000 characters. Opera 9 for Windows continued to display a fully editable, copyable and pasteable URL in the location bar even at 190,000 characters.

Source: http://www.boutell.com/newfaq/misc/urllength.html