Slayer or Construction.
For slayer, its just kewl to see the creepy new monsters you can kill after an assignment or two. Slight chance of death, and you need a
lotof food, but all in all the profits outweigh the losses (unless you lost your rune set to that stupid *insert monster here*...)
As for Construction, it may seem expensive and useless, but having level 70s gawk at my house (41 con w00t!) gives me a sense of fulfillment. Plus, there are places to train your magic, range and melee, fight other players and teleport without needing law runes! Also, don't forget the chapel (extra prayer xp for bones) and the study (spells on clay tablets).
I voted construction
