Smithing is probably the most respected out of the bunch.. I'm pretty sure it's every noob's dream to have 99 smithing so they can smith full rune, lulz.
well everyone has different opinions but my ones are:
agility + construction/prayer
agility is free and wont use money but con + pray will use money and are both skills especially if you wna show off as you can make brilliant houses with con and have ultimate monsters