Gears of War is fun, but yeah I'd say its story is fairly mindless. The idea is fine, but I always find myself asking why they don't just open up a whole underneath Marcus Fenix's improbably armored ass and pull him under.
God of War, at least the original, is an entirely different beast. The original's story is smart, interesting, extremely well-told, and engaging. Most important of all, it establishes the antagonist as more of a bastard than the protagonist.
The second game and the PSP games were very fun and their story was understandable, but after finishing them I knew what it was like to play the badder guy. While I did enjoy the later installments, I think the franchise would have been better if it were left off after part 1 or 2. I haven't finished the third one but I know that its story makes Kratos a complete and utter bastard, at least until the screwy turnaround at the end.
Hope? Really? From Kratos?