Red Bull if you're in the US.

thought that's a small, german thing

In the US it's an "I read 2600 Magazine and go to HOPE and I have a point to make" thing.

I mean, it tastes good, and it does carry a decent punch in terms of caffeine. But coffee's a lot more convenient, and you spend less time explaining it.

Also cheaper.

Not anymore. Saw plenty of club mates at defcon talks.