I gotta give a +1 to the proclip mount. it's cheaper than the seidio one, and integrates better, no suction cups to fall off.
you can also use all the cables, chargers and stuff with your phone with the mount. i prefer this since i liek to use my mogul as an mp3 player thru my stereo. with the seidio mount,
afaik, they don't have a stereo output on any but the most expensive model.
but it's $70 to get you started, fyi.