RAM-B-149Z-PD3u : Otterbox.  Great protection but adds bulk.  This mount uses a heavy composite plastic cradle that is spring loaded to grip your Otterbox encased device securely.  Fits handlebar diameters up to 1.25 inches.  The mount itself is constructed of aluminum and comes with a manufacturer lifetime warranty.

Cradle Clamping Dimensions:
Height Range: 4.75" - 6.25"
Width Range: 2.25" - 3.25"

Fits many models including:

Apple iPhone 3 3G 4 4S

Blackberry: 6230, 7200, 7230, 7250, 7272, 7280, 7290, 7510, 7520, 8700c, 8700r, 8703e, 8800, 8820, Bold 9000, Bold 9630. Bold 9650, Bold 9700, Bold 9780, Curve 3G 9300, Curve 3G 9330, Curve 8300, Curve 8310, Curve 8320, Curve 8330, Curve 8500, Curve 8520, Curve 8530, Curve 8900, Curve 9300, Curve 9330, Pearl Flip 8220, Storm 9530, Storm2 9520, Storm2 9550, Style 9670, Torch 9800, Tour 9630

HTC: Aria, ChaCha, Desire, Desire S, Droid Incredible, Droid Incredible S, Evo, Evo Design 4G, Explorer, Gratia, HD7, MyTouch, Paradise, Radar, Rezound, Salsa, Sensation XE, Sensation XL, Surround, Titan, Titan II, Vivid

LG: DoublePlay, Eclypse, Maxx Touch, Maxx QWERTY, Nitro HD, Optimus LTE, Prada 3.0, Revolution, Spectrum

Motorola: Cliq, Cliq XT, Devour, Droid, Droid 2, Droid 2 Global, Droid Pro, Droid R2-D2, Droid Razr Maxx, Milestone

Samsung: Acclaim, Alias, Behold II, Captivate, Charge, Continuum i400, Craft, Dart, Droid Charge, Epic 4G, Eternity II, Evergreen, Exhibit 4G, Fascinate, Focus, Galaxy Ace,  Galaxy Indulge, Galaxy Prevail, Galaxy S, Gem, Gravity Touch, Infuse 4G, Intensity II, Intercept, Mesmerize, Moment, Mythic, Nexus S, Nexus 4G, Omnia II, Reality, Restore, Rugby II, Seek, Showcase, Sidekick 4G, Smiley, Sunburst, Trender, Vibrant

Sony Ericsson: Xperia X10