P.S. I want both of these on T-shirts. STAT.
But I digress. My preference?
Here's the thing: when I played as a straight renegade, I was BroShep. I couldn't do it as FemShep. It's not like I believe that women are incapable of making brutal choices, but being that I am also a woman, I identify with her more and can't see myself being that extreme. But with BroShep, I had less of an issue being a success-only minded jerk.
And this is where I go into my feminist rant, because seriously, did you expect me not to? Women need more protagonists that match their gender. Not all women are the same because, guess what, we're human, but as far as I'm concerned, I feel more emotionally connected to female characters; I can transport myself into their shoes, particularly in a game like Mass Effect. As the video game industry sees more women entering its demographic, it needs to recognize that, in order for many women to immerse themselves into the game, interesting, multidimensional female characters need to be making more appearances and not just for sex appeal.
Anyway, ahem, about that paragon v. renegade issue. My ultimate playthrough was with a primarily paragon Shepard, with about a 1/3 renegade bar filled, which I felt was a good mix. After all, I'm a fairly flexible person who can see the benefit of a not-so-nice response to something, but ultimately, I'm all about helping the whole, not the one. There were a lot of times I chose the renegade side of things because I just wanted a scene to end; on Mordin's loyalty quest in ME2, the Weyrloc guy who just keeps taunting me with visions of the great krogan expansion made me irritable enough to blow him up with the fuel tank, for example. I also chose to kill the rachni queen in the first game because 1) I didn't want Grunt to be upset with me, 2) I wanted to be able to keep the whole Aralakh Company, and 3) I wanted to see the email message that Grunt sends you if you're able to save his unit. Like I said, though, as a general rule, I stayed on the paragon path so, at the end, it really is the entire galaxy coming together to throw whatever they have at the Reapers, instead of a soldier just going around and bullying people into it. It just seemed, to me, to be a better approach, and apparently, nearly 65% of everybody agreed with me. So there. I win.