How was Trezor (bitcointrezor.com) not mentioned here thousand times already? It's a 100% solution, an offline, standalone signing device. It's open source and it's securing bitcoins by the design of the process alone and not by a smartcard component like ledger wallet.
1) Expensive.
2) Not offline(aka cold storage).
Ledger is secure like Trezor. Don't think Trezor > Ledger!
