Maltheism: The belief that [a] god exists, but is not omnibenevolent, and possibly dualist. See also here and here for more information.

I find this a fascinating idea, and am quite frankly suprised I haven't thought of it before. Alright, so God exists. But he/she/it is actually much more like the Greek and Roman gods - enjoys wreaking havoc every now and then. Satan is actually a psuedonym created so he/she/it can appear good, while still getting to cause suffering.

I think it's summed up beautifully in this [paraphrased]:

What exactly is God saving us from, if not his own willful wrath? Isn't that akin to calling a bully your savior for not beating you up when you give him your lunch money?

So, God's a bully. Or put slightly more extreme (and more accurate, if indeed God is responsible for so many deaths), a terrorist. Makes you want to run right out and give thanks, doesn't it?