There are a series of questions that can lead you to the final choice.
The first one and most significant - do you want interchangeable lenses, or just one camera to carry and "do it all"? The significant difference is the long end of the zoom. AFAIK, no self respecting interchangeable lens camera does much more range than c28 - 135 35 mm equivalent.
If you do, m4/3 provides a host of options than combine size with decent image quality.
If you want a "travel camera" to do it all then budget is a determining factor.
For my money at the moment, the Olympus SH-1 does a decent job, 1/2.3 cmos sensor, 25-600 lens, 5-Axis IS, £160. Just bought one recently for Mrs Ham and it performs very well for the money.