Mountek CD-Slot Mount (Amazon)
Thought I would add my experience with Amazon's top-rated universal mount.
I ordered this one so my wife and I could both use our phones with it. I wanted a mount that would put the phone as high up as possible without blocking part of the windshield, and in my CR-V the stereo is at the top of the dash, so this sounded perfect.
It's a solid mount but maybe not ideal for the Lumia 900. Since the buttons are on the side, the side clamps block the camera button and most of the unlock button. I'm gonna use an eraser or something to put underneath which will make it the perfect height. You could also remove the bottom support, but since the phone is pretty heavy, I'd rather not. The weight of the phone also makes it pivot around a little easier than it should, and if youre driving on bumpy roads, the phone will shake a lot in the holder. However, it holds the phone snugly in portrait or landscape and the placement is perfect for my car.
Those are my main concerns, but they're not deal-breakers for me so I like this mount for my car. The location of the phone is really where I want it to be.