How many of us genuinely enjoy playing 'evil' characters?

Of course RPG's provide us with the option to live our power fantasies (and romance fantasies) in some way, that's one of the main reasons we play and love those games. 
Personally though, I try to make characters that closely resemble my real self, I feel too disconnected with characters that are vastly different than me and then immersion suffers which is the most important aspect for me. I guess I'm really bad at roleplaying.
Though I'm pretty cool in real life so its not that much of an issue.   /jk

To be fair, if you like who you are, why would you want to pretend you're someone else?

I just go with what feel right most of the time. I could never kill the rachni queen and the one time I poisoned the Urn it was just to get the reaver specialization and abandoned the playthrough. There were a few times I did a "bad" decision in ME2 so I could open dialouge options. My point was that it is unlikely I would be that good and selfless in real life. I like to think I would be but I would not charge a templar or an angry mage or an ancient darkspawn.

It did. I got the specilization for my future playthroughs but canceled that one.

I rarely play evil characters, but pragmatic/renegade all the time. I could play a evil character if it was well done, but unfortunately almost all games are like ludicrous evil and I can't buy in.

Yes and no. I do get a kick out of playing a character who is gonna be a dick to everybody and kill everything in sight.

However, I never get invested enough to roleplay an evil character as seriously as I do the good guys.

I sometimes try a few evil choices out just to see what happens, and occasionally I try out a “pragmatic” character when ruthless but not necessarily malicious options are available.

I pretty much always default back to a goody two shoes character though.

Well, at least you can say you tried evil on the game that allows it the best.  I only did one Dark side run of KOTOR, but it was hugely satisfying.  Horrific.  But satisfying.

It did have a great ending cutscene, especially the Infinite Fleet part. Can only imagine what that’ll be like in the remake.

I love playing "evil" characters, but only when there's a psychologically coherent personality to them. Exploring vices and phobias and the brutality of different worldviews from your own is half of what I enjoy about roleplaying, but a character can't be ALL vices or phobias or brutality. There has to be a second and preferably also a third dimension to them, or those evil or morally questionable actions don't actually mean anything in terms of why people do the things they do. Which tends not to be "because I've just decided to be a dick through and through".

For example, playing through the entire Mass Effect trilogy picking only one viscous Renegade response after another seems completely pointless and boring to me, while playing a Shepard who makes almost all those same decisions and comments while showing just enough occasional tenderness, understanding and sympathy to make it clear that they're a human being at heart makes for a much more interesting playthrough.

And the same goes for vice versa. A completely positive and altruistic and idealized feel-good playthrough of anything seems meaningless. There has to be at least enough darkness and weakness and even malice to show that the protagonist is human under those strong principles, or those "good" decisions have less than no value. Because they don't represent thought or choices, just a dumb blanket decision to "act good" the way you see things beforehand. Yawn, and... eeew. No thanks.

Same. I like the evil playthroughs, but you have to make an RP and rules and values you stick to otherwise you just have this nonsensical playthrough.

For example, I love playing my slightly psychopathic trio of power-hungry mages, but all of the choices they make in the game are motivated by 1) furthering their own power, and 2) acquiring forbidden knowledge. For this reason, my Warden mage sided with his fellow Circle mages over the templars, but also sided with the Spirit of the Forest and werewolves. Simply clicking through and picking the "bad guy" options is not fun.