- Code complete: Omni completion or Clang autocomplete or YouCompleteMe
- Real time syntax checking: Syntastic
- Switching between source and header file: A plugin
- Snippets: Snipmate or UltiSnip
- Search for reference of variables, functions, classes, etc.: Cscope
- Go to definition: Ctags or part of YouCompleteMe subcommands mentioned above
- Refactoring tools: Refactor, lh-refactor
- Useful text objects: Arg text object and Class text object
- C++ category in Vim Tips wiki
- Luc Hermitte’s C/C++ plugin
- Not C++ specific but I also recommend either FuzzyFinder or Command-T or Unite for file navigation. With either of these, you don’t even need tabs (which does not scale for 10+ files) to manage your project.
- Class navigation: Taglist or Tagbar
Edit: Updated as of July 2013