Effective edge is what you want for hardpack, this is why racers, alpine boarders, and carvers use a board shape with a MUCH longer effective edge than us. I know some guys love the mange-traction, frostbite edges, etc. but I have yet to see any racers win on boards with bumps in the edges.
So ultimately, if you want to stick with a traditional board, look for something with blunted tips.
My board is a 160 and has over 140 cm of effective edge, while most 160 cm boards have somewhere from 120-125 cm effective edge.