I think you should be looking towards a downloadable wallet with a locking/encryption mechanism. Most wallets do have something of this fashion. This way, your wallet is password protected so even someone with physical access to your machine doesn't have direct access to your funds without you having entered the password. Having your wallet at a secure machine is also vital however. In general though, you wouldn't want to store large amounts of BTC to the same machine that you use to casually browse the net, download files, install third party programs etc.

I think multibit is a great option for such a thing.