Well, my opinion on the current debates:

FFVI/VII: I haven't played these.

Halo: True, I do agree the level design could have been better, because all of those hallways got old fast. However, it's still a really good game that helped Microsoft establish itself as a valid gaming entity.

MGS: I've barely played the first Metal Gear Solid, and I can't get much further. I'll have to play it more before I make a final decision.

Half-Life: Haven't played either of these in my life.