I would go for 17-55mm efs 2.8 (a bit more tried and tested and highly thought of than the Tamron, it stays on my camera about 90% of the time) + 10-22mm EFS, these 2 lenses would have you well covered and you have the 3x digital zoom on the 70ds when you need to go long, and the 50mm prime for beauty shots, although 50mm on a crop sensor is quite tight..