Hydrogen is usually considered the best carrier gas for use in GLC (gas liquid chromatography). The flammability leads to safety issues, which is why hydrogen is not used often. Some manufacturers use pressure sensing technology to sense a leak and automatically shut the gas flow off in case of a hydrogen leak. Helium is non-reactive, so it is the most common carrier gas. Others like Argon, etc, are usually used only when some special condition requires it.
Some professionals will refer to GC as a "modified boiling point separation technique". Usually, a GC method makes use of a temperature gradient method. You start the run at a low temperature (say 40C) and ramp the temperature up over the course of the run (sometimes to as high as 350C). When a method uses this kind of temperature gradient, the boiling point is the most important characteristic for separating the individual compounds.
Sometimes, GC will be run in an isothermal mode (same temperature for the whole run). Then the boiling point rules don't apply.
Hope this helps.