I could never get into the Half-Life games. God knows I've tried, I had the first one on PC ages ago and I've got a borrowed copy of The Orange Box sitting here on my shelf, just above my eyeline as I type this, but I just can't bring myself to care. I'm not entirely surprised by this because I don't like FPS as a rule. The main reason I borrowed my brother's copy of The Orange Box is because several people who know about shooters told me that Half-Life 2 would be the game to make me love the genre. In that respect, I was disappointed... although it did introduce me to Team Fortress 2, which remains the only proper FPS since Goldeneye that I've genuinely enjoyed.
I own a couple of other shooters, mainly as part of the experiment to see if there was any that I liked. Halo 3 was the first in the experiment, got bored of that within a couple of hours - if I'm gonna play a shooter, I'd rather be using guns instead of things that look like toys I had as a kid. Call Of Duty 4 was the most recent, not bad, still not really my thing but I got distracted by other things in life before I could properly get into it... thinking I'll have to start again now.
As for games within genres I'd normally be expected to like: Mass Effect. Oh, Mass Effect. At the time, I lived with two huge fans of the game. I like RPGs, so decided to give it a chance. First time I tried it, most of the few hours I played were spent reading enough text to make the Encyclopaedia Britannica jealous. I got to... some place or other, got told I was a Spectre, read more bloody words before abandoning it soon afterwards out of sheer boredom. Second time I tried it - for some reason I decided it deserved a second chance - I played for half an hour, then *fizz* *black screen* "oh no, seriously, no..." *restart Xbox* *lolredring* "fuck you, buddy". Yup, my Xbox actually committed suicide rather than let me play that game. I took it as a sign and haven't considered playing it again.