I disagree with all this 900 craze making HTC look like chumps. The TITAn II improves upon an already proven WP in amazing ways. The camera is also sure to be better, the shots from lumia 900 are no where near as sharp (still crisp though). HTC titan is actually lighter and thinner despite it's bigger screen. The build quality is all there and HTC has a very strong app store already.
It comes down to complete opinion and I am extremely torn. The money is irrelevant, 100 bucks over 2 years is so cheap, the cost benefit of having the phone i prefer is worth more than that. As of now my opinion is not made up, my decision will be made in store after hand on session with both. I am debating waiting for the white 900 on the 22nd so that reviews will be out for both by that point.