I just finished my first playthrough 2 minutes ago, went through the complete credits listening to the wonderful soundtrack. What a wonderful game this is! Damn, I'm so glad I discovered the first game a couple of years ago, this is gaming as it should be! I'm in awe, still think the first game was superior but it's just nitpicking. Thanks CDPR, the world would be a poorer place without TW and the people who created this game. And the music, of course.
On topic, I didn't kill Letho. My first playthrough was Iorveth's path and killing Leto just didn't feel right and coherent with the choices I made throughout the game. My Geralt is a neutral kind of guy, trying not to judge others, trying to be tolerant and have some sympathy for the wretched souls that populate his particular world. I made one wrong decision in the game though, but at the time I wasn't aware it would bring the consequence it did. I let Stennis get killed.
Anyways, I'm surprised by the percentage of players who let Letho live, thought everybody was into kills and raising statistics lol.
I plan to fight Letho in my next playthrough, in October, when I'll be doing Roche's path, once the 2.0 patch gets released. There will be no mercy next time, lol, I'll fight absolutely everybody who can be fought, my next Geralt will be a ruthless killer. But the savegame I intend to import to TW3 (if there will ever be one) will be that of my fist playthrough: Iorveth's path and Geralt the Good Samaritan
What a great feeling, I just completed one of my favourite games ever and the day after tomorrow I'm leaving for a scuba diving vacation, life can be good sometimes
PS
Oh yes, I definitely hope to meet Letho again in TW3