Brain wallets, paper wallets, and deep cold wallets are additional excellent ways of creating a secure wallet for occasional transacting.
What's a deep cold wallet?
And how about a small TrueCrypt volume, stored on a remote server? Not in www of course, and with a very secure hard-to-crack password.
That's what I was thinking, make a TrueCrypt container n keep it somewhere safe, or perhaps put it on a TrueCrypted microSD or USB stick or whatever. A hard to crack password doesn't necessarily need to be hard to remember. While lots of variations in uppercase/lowercase/special characters does increase the security of a password, so does length, which is why TrueCrypt advises a pass of @ least 20 chars.
So you could just take a pass like e.g "Itakemydogforawalkeverymorning!" (basically I mean something easy to remember 4 you, I don't have a dog btw, this was just a random example that popped into my head), it'll be pretty secure. Be aware that TrueCrypt only allows up to 60 chars. for a password, though. If you are on Windows and want an open-source alternative (TrueCrypt has a modified version of GNU) I'd suggest DiskCryptor. Both have their advantages and disadvantages but if you want details about the differences I suggest you use wiki and/or Google.