Raina looks like the best prospect among the younger bunch...Nobody has shown the likelihood of a future Dravid or Sehwag anytime soon, let alone future Sachin...But Raina looks like he can give us the next Ganguly (the batsman, not the captain) if he keeps his feet on ground...
Kohli and Rohit, while both are talented, look like they have temperamental issues like Yuvraj, besides some technical issues.
If Kohli does his best, he can give us a very poor man's Dravid at best (not sure about tests, but in ODIs that might be the case).