Though a bit dated, I thought I'd bump this one back up to the top of the thread!
Good suggestion, but Golden paper wasps are much more 'hornet looking'.
This one is a Short tail Ichneumon Wasp, an important biological control species. You've probably seen other Ichneumon wasp species over the years - they're the ones with the long, thin, 'stinger'-looking protrusion used for parasitizing live caterpillars with eggs. Don't search for photos of Ichneumons though because their colour and pattern range can be quite diverse. Even specifically searching for Short tail Ichneumon Wasp will lead to 11 different species of them alone! I've got years and years of entomology under my belt and I still wouldn't have a chance of narrowing it down to one of those 11.
