Half-Life 2: I'll admit it's a good game, I liked playing it, but I can't say I was blown away by it or that I found it to be truly amazing. I guess it's due to when you play it; I first played it in 2011, but it was ahead of its time when it first came out, and if I played it back then I would have had a better opinion of it. But since I played games that have take HL2's ideas and made them better (well most of them), I can't give it the praise everyone else has.
Call of Duty: Until they actually try something new, rather than adding a single game mode in, or putting in a weapon with new mechanics that noone uses anyway, I also don't see my opinion getting any better. Wager Matches in Black Ops were a good idea, but by not allowing you to rank up with them made them useless in my opinion. You can earn money with them, but that's all you could gain. I enjoyed playing them nonetheless. They also should have allowed you to rank up while playing Zombies, that would add to your multiplayer rank. By not doing this, all we do is play the same modes and rank up with them like we've done since CoD4.
GTA IV: While the realism was appealing when I first played it, I found it to be boring. So boring, that it took me almost half a year to beat it, because I invested very little time in it. Really, the realistic rag dolls were all the GTA series needed.
GTA III: My first GTA games were games that came after this one. So playing this one feels like a step back, much like with Half-Life 2. Once again I admit that this is a great game. You get to kill people within the first mission or two unlike GTA IV, and I respect that the game gets right to the good stuff quickly.