What is the best mobile phone privacy? PUA?

I tried to buy one of the latest smart phones, such as iPhone 4, HD7 HTC, BlackBerry 9800 calls etc, but I want a phone with a good privacy settings I like to use the phone as a sort of journal and books self-help policy and acceptable use of audio, such as PDF and web sites. I would be ashamed if someone was to borrow the phone and see what kind of things so my question really is that any applications or privacy settings built in built in recent smartphones that can restrict such things as: – the history of the site – password protected files – the audio tracks that are not automatically added to your library of songs, thanks in advance

N8 Unlocked GSM Nokia touch screen phone with GPS, voice navigation and camera 12 MP – U.S. Version with Warranty (Gray) Unlocked quad-band GSM 850/900/1800/1900 compatible cell frequencies and the support of the United States / International via UMTS 3G 850/900/1700/1900/2100 / HSDPA and GPRS / EDGE enabled 3G smartphone capabilities gray, with 3.5-inch AMOLED touchscreen ^ 3 and Symbian OS 12 MP camera with Carl Zeiss optics and recording 720p video, Wireless-N Wi-Fi, Bluetooth 3.0, 16 GB of internal memory, microSD expansion, an HDMI 5.8 hours of 3G talk, 400 hours (16.7 days) timeout, published in August 2010, What's in the Box: phone, rechargeable battery, compact travel charger and connecting cables, HDMI adapter, a USB adapter, wired stereo headphones guide, quick start …………

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