If open source is your thing with money being a bit tight and you don't already have some sort of inbuilt hardware solution via a TPM, here's one of the most talked up real time encryption utilities out there in its latest iteration for the price of what you already paid for your gear that you intend to down load it with and use it on. The only problem is that you need a pretty hefty processor in order to get it running in real time with a relatively negligible performance hit.  However it looks like the latest version 7 remake of truecrypt has native Intel support features that utilize the capabilities of the latest corei5 and corei7 processors in order to achieve what might be even faster seamless and transparent on the fly encryption and decryption. Now to figure out a way to afford all this new gear for the sake of increasing security and being able to still work unhampered. You know, just in case you've got a bunch of unencrypted hidden partitions on your system whilst using the internet or have drives in your bag with personal files and important projects or a shed tonn of porn that people seem to be getting into whenever you leave your bag unattended.

Its funny, with all our advances in IT, real time tracking of our activities and our ability to produce multicore-multi-gigaflop churning machines, it’s a wonder they haven't figured a way of intelligently allowing authorized users to access their files whilst disallowing others seamlessly. Maybe they could use some sort of proximately detection drawing on many sources of verification such as proximately detection of other digital devices near by whether via rfid or the none consumer accessible portion of Bluetooth, voice detection using their machine and additional confirmation via nearby cell phones, maybe some sort of discrete iris scanning mechanism via the screen, unique RIF checking against commonly worn items of clothing, registered details of OS user accounts and verified login details, facial recognition via the screen or webcam, It might be worth considering since people in many respects have already been moved to the cloud involuntarily without even knowing it. Sure I reckon one of the 8 processing cores of an i7 could be purely given up for that sort of thing with no noticeable performance cost to the end user whatsoever.