I really liked Saren, I felt sorry for anyone who never played the first game because there was a villain executed to perfection, it really got you thinking about how his mind worked.
Odd how he hates humanity so much and yet he perfectly orchestrates the human way of clinging to life no matter what, when you boil it down Saren was only misguided and manipulated (the books didn't paint him in a pretty light, but this still applies), so it really felt good when you got those speech challenges done and inevitably make him see in his last moment of clarity the gravity of his mistake.
A grade story writing in ME1, just wish it transmitted to the final game :/