If you are hoping to build typical web applications, you should probably learn PHP or Ruby (and Rails), along with JavaScript, HTML, and CSS. There’s no reason you could not use Python for this work, but it is not typical to do so. PHP and Ruby would give you access to a lot more existing web applications, frameworks, and web development tools.
If you are looking to use programming skills to directly accomplish tasks, such as automation or analysis, Python is an excellent language for that sort of work and is where it gets most of its use.
If you are building apps that need to manipulate data in a specialized field or domain — such as math, science, finance, music, or cryptography — Python is an excellent language for these sorts of projects as well.