I wrote up some weapon enhancements with the assassin class in mind. Posting them here in case you guys might wanna use 'em. If so, tell me what you think.
Death-dealing (+2,000 gp): An assassin wielding this weapon increases the DC of his or her death attack by +1.
Venomous (+1): A venomous weapon adds its enhancement bonus as a bonus to the DC of any poisons applied to it. In addition, the weapon allows the wielder to use a poison effect (as the spell, save DC 14) upon a creature struck once per day. The wielder can decide to use the power after he or she has struck. Doing so is a free action, but the poison effect must be invoked in the same round that the weapon strikes.
Vampiric (+3): Functions as wounding weapoon except that the the heal DC to stop the bleeding increases to 20. In addition, any bleed damage dealt by the weapon heals the wielder (for example, after having been struck three times by the weapon, a target bleeds for 3 points of damage at the start of its turn, the wielder of the vampiric weapon would then gain 3 points of healing). Hit points gained from this weapon cannot exceed your maximum hit point limit; hit points gained in excess of this limit are lost.
Occult (+2): The damage caused by this weapon doesn't heal naturally and resists magical healing. A caster attempting to use magical healing on a creature damaged by this weapon must succeed on a DC 25 caster level check, or the healing has no effect on the injured creature.