Im sorry but I need to completely disagree with almost all of the answers to this question. Some of them present perfectly good situations where you may not wish to use the default language, but these situations account for less than 5% of use cases. Why bother the 95% of cases where the default is acceptable?
Imagine that the language of the page and default location was set in line with the browsers configuration. 95% of people will now be able to browse the website in their desired language without having to specify it. To cater for the 5% who wish to change language, simply display a prominent "switch language" or similar button.
The alternative is to ask every single user to pick a language, inconveniencing 95% of the user base who simply select the default anyway.
Why would you choose to inconvenience every user, when you can only inconvenience 5%?
Unfortunately web developers tend to follow existing trends rather than think about what they are doing and provide appropriate solutions.
Also, bear in mind the OP is talking about setting the language based on the browsers language setting, and NOT based on IP address. Therefore working over VPNs, proxys, travelling abroad etc will not affect this setting, and will continue to display the appropriate language to you.