I use a Mach 3 with King of Shaves oil and gel. The oil by itself won't quite hack it, but with the gel, great results. I ran out last week, grabbed my old can of Gilette gel, and I got a lousy shave, comparably.

The oil bottle is obviously very small (15ml?), and I usually transfer the gel into a little 2oz Nalgene screwtop bottle I got from surplus at work - roughly the size of a small pill bottle. That'll last me for about 3-4 weeks of travel.