Armory offline wallet is the best. Use it on a permanent offline PC and interact with a USB stick through it. Make sure the hard-disk is encrypted and also hide your passwords very well, its the best security that i can think of, secure enough to hold 1 billion $ woth of bitcoin in it.
But only if you know how to secure it propertly.
Otherwise for smaller sumps Xapo, Blockhain.info and other online wallets are pretty decent too.
I recommend a Qr Code over USB. See
https://github.com/hank/armorycompanion-python/Well i use an empty USB, unless the virus can put itself there without i detecting it its very unlikely.Also reformatting it after every use, just for safety.
Also you can use a different CD every time you use it and burn it the offline tranasaction file to it.
The QR Code looks nice , but then again the risk is that it can have a backdoor and put more info in that qr code than needed...