I never even played Metal Gear Solid. The fact that the (recent) MGS games are console-only is a reason. I used to be addicted on AoE2 too, but HL still rules for me. HL2 is great too, though it was more because of the graphics and various locations, it was less scary than HL1, though I didn't really mind that. Haven't played Mass Effect yet either. If it had had MP, I'd bought it on Steam with the Holiday Sales.