Sachin and Don for me. Arguably the greatest players of their generations. I can say Lara also, but he's not got a great record in ODI's compared to Sachin. But Sachin has got a great record in both ODI's and Tests. I think it'll be a long long time when a player can break Sachin's overall records.
Warne for me has not played well in ODI's but sensational in tests and so I can't say he's the greatest player considering both forms of the game...
So finally for me:
In Tests I'll go with Don and Warne
In ODI's I'll go with Sachin
Overall I'll go with Don and Sachin...
