Yes: If you don't use and don't plan to use any IDE in future. And even if you use an IDE you will find yourself returning to it to do many things. In vim you van write scripts, do complex tasks like instead of individually editing 500 lines do it with a (slightly cryptic but easy to understand once you pick up) command. I initally found it difficult but later it has helped me lot. Even the best IDE's editor will lack the power of vim. Vim can work well with CVS, SVN, make, debuggers etc.
No: If you will stick to IDEs like Eclipse or Netbeans. Or if you find that editors like Kate are enough for you. Infact Kate or Notepad++ or jEdit have GUI and features you may miss in vim. e.g. Kate's symbol viewer or Notepad++'s huge menu bar.