I'm in the market for a USB flash drive, and remember this cool feature a tiny 32MB flash drive of mine had: a write lock switch. This seemed like it would be an amazing feature to have as a shield against any nastiness happening to the drive on an unfamiliar computer. However, very few drives on the market offer this feature. Instead, it seems that forms of software protection are the more prominent method.

This software protection causes me a bit of uneasiness, as it seems like this software wouldn't be nearly as bulletproof as a physical switch. Also, levels of protection seem to vary from product to product. Being able to protect certain folders from reading and/or writing would be nice, but is the security trade-off worth it? Just how effective can this software protection be? Wouldn't a simple format be able to clean any drive with software protection?

My drive must also be compatible with Windows XP, Vista, and 7, as well as Linux and Mac.

What would be the best way forward for getting a well-sized (~8GB) flash drive with a strong write protection implementation, for little or no more than a regular drive?

Thanks.