Another Marylander for backfin.
I don't know how it is where you live, but here we have "backfin" and "backfin lump." Plain ol' backfin is fine for something like dip. But, if you really want your crab cakes to be good, go for backfin lump. Last time I looked, lump is about $29.00 per pound, so we save it for special occasions, like Christmas.