The Gerber Shard hooks onto your keychain and provides several tools any DIYer needs on a regular basis. You get a two-sized flathead and one philips head screwdriver, bottle opener, wire stripper, lanyard hole, and a pry bar in one tiny tool.
The Shard (pictured above) was designed for safety so you could carry it around without hurting yourself (or anyone else). It's even allowed on aeroplanes. If DIY projects and/or handywork is a common thing, and you always want to be prepared when you need commonly helpful tools, you can fit them all in your pocket with this clever little thing.
While there doesn't appear to be a local distributor in Australia, the tool is available on eBay for around $7-$15.