Garfield sobers and Malcom marshall probably.one thing is always surprising for me,how much little marshall played at home,out of his 81 tests he just played 31 matches at home.(To compare, McGrath 66-58 home, Ambrose 52-46 home,hadlee 43-43)Also,with due respect ,i don't get the comparison with hadlee.l mean,I know hadlee was the lone genius in that mediocre NZ team.But against Pakistan, hadlee took 51 wickets from 20 innings@28.3 and marshall took 50 wickets from 23 innings @20.7.Also hadlee played just 3 tests in Pakistan, whereas marshall played 10 tests in Pakistan.You can say, marshall was a part of the more potent bowling attack,hence his job was easier.But,this stat is quite decisive for me.