Been to Spain three times (I'm jealous, John from PA!). Only the last time did I have a digital camera. 7D and Sigma 17-70 OS. Great combination and, while I would have liked to have something longer for detail shots, especially in churches, I never really missed anything by having only the one camera and lens. I have a Canon 50 f/1.8 and brought that but never used it.
So my recommendation would be to bring just the 7D and 17-85. I would not bring the flash or tripod, but a gorilla pod, assuming it can handle that camera/lens combination, might be worth carrying.
Tim

I was in Spain for 4 weeks this summer, traveling through Madrid, Barcelona, Sevilla, Toledo, and Pamplona (for the San Fermin Festival). I drank the water from the street faucets and ice cubes with no issues.
