Private key security is a serious business.
Last Bitsafe was just a fake prototype with no real security in mind.
Bitcoincard is pure vaporware with unrealistic Xfiles-like features.
Paper wallets are not real day to day convenient solutions and do not cover the secure spending part.
For now, the only existing secure hardware wallet is the HW1 from http://www.hardwarewallet.com : this is the only solution based on a secure element (smart card) and made by security experts. I recommend to use it (not mandatory) with the Green Address solution, the two teams worked together to obtain the most secure and full featured solution (2of3 multisig, instant spending, and you can backup your seed on paper if you fear hardware failure...).
Trezor is a nice solution, with a nice team... but this should not be considered as a secure solution. We hacked it once and made a first report (this was patched). We will probably make another security issue report soon, we are a bit surprised to be the only team to challenge their solution, please do not put too many confidence into it.
Our own PRISMicide foundation is working on the open source & open hardware Bitcoin Pinpad project (new name for PRISMicide for Bitcoin), which add another level of security and smart phone / tablet compatibility to secure elements like the existing HW1 and and the future open source MicroSIM based solution. (Bitcoin Pinpad is a small portable device with USB and Bluetooth connectivity, you can follow the hardware side of the project on http://www.origamiboard.com)
[Edited note : part of the BTChip team that brought HW1 hardwarewallet.com is working on PRISMicide projects too...]
By the way, there are very few hardware wallet projects with real security in mind but USB Armory is worth a look too : http://inversepath.com/usbarmory
