Goosmo

Do what hitsusan says if you are starting. Blender may not be the best, but it does the job well enough, and it's free too. I personally use it for both retopology and uv mapping. You can also use the sketchfab 3d viewer on tennogen models on the steam workshop to see how others have split their uv's and their retopology.

Any plans on letting us make skins for more basic melee weapons like dual swords, machetes or scythes?