I did parts of Europe with a a 20D, 11-18, 28-75 and a cheap 2x (worked ok on the 28-75 if stopped down just a touch, surprisingly). The 11-18 and the P&S in my pocket ended up getting the most use. If I did it again it'd be an ultra-wide, a longer small prime (i.e. 85 F/1.8 for APS-C) and a nice P&S. It depends on how you like shooting though.