Well, it depends on your finances, too. Is either tank drilled? The 92 corner would make a spectacular reef tank but lighting it will be much more of a challenge (at least to your wallet) than lighting the 75. Personally I'm not a huge african cichlid fan but with some cool rockwork in the 92 it would be a great display tank for them too.
Oh, and I wish I had your problem

I'd kill for either one of those tanks!