My cross bike is setup for light touring and my trip later this month will be going through lots of hills and mountains in Switzerland and Italy. I'm a pretty strong rider, but I wanted lots of extra gearing for some of those long climbs and/or pitches that were steeper than expected, and just to be able to take it easy when I want to. I'm going with compact cranks (50/34 175mm) and a 11-32 cassette, and that gives me about 3 lower gears than I'm used to. I also swapped out my rear derailleur to a medium cage to accommodate the larger cassette. I have a more detailed explanation about it on my blog (link in my sig).