Definitive build:
Master Stone Strike
Master Sixth Sense
Master Shuriken Toss
Level 1 Armor Destructor
Master Lucky 7
Master Landmine
Master Aura of Luck
Master Explosives Expert
Level 10 Hiding
Master Sudden Attack
The following skills are luxury skills and are to be acquired if you have lots of spare TM, in order of usefulness:
Sticky Icky: If you like to PvP and Boss alot (requires level 10 sticky foot and level 10 armor destructor, though)
Heavy Carrier: If you like to carry lots of items (I have this mastered personally and it rocks)
Basic Detection/Item Detector: Helps in drilling, but I'm not too fond of these skills as 90 DA (which you'll be reaching) gurantees if you'll know an item is underground or not
Gun Booster: If you want to cut off a meager 9 HV from enemies...
Every other skill sucks, don't get anything not mentioned here.