If you are set on CS, and assuming you would actually be paying $$$ to attend Duke or Dartmouth, then it’s a no-brainer: Georgia Tech.
But if it’s not that simple, as in:
- If you are also considering Finance/IB as a career, then Dartmouth and Duke are both sought after by Wall Street and firms elsewhere, much more so than GIT.
- If cost is low enough at Duke and Dartmouth that you could easily afford them, you might still consider Duke and Dartmouth. Neither is as strong as Tech in CS, but they are strong in a plethora of other majors, so if you aren't sure about your major...
Based on what you have said, GT seems like the best choice.
If you keep the D schools in the running, know that Dartmouth and Duke are close peers so assuming cost is close between them, choose based on fit. There are gobs of differences between them – size, location, setting, weather to name just four big ones – so go with your preferences.
In sum:
- If you are 100% sold on CS as a major and a career, choose Tech.
- If you are not, and especially if you think you might drift over to Business/Econ/Finance or the humanities, you would probably be better served at Dartmouth or Duke, as they are both stronger in those areas than Georgia Tech. (unless they are not affordable, of course…)