I for one would like to see you avoid Assassin & Imaskari Vengeance Taker.
While Death Attack & Target of Vengeance are flavorful, there is no reason to kick your self in the balls for flavor. ToV is worthless to your average adventurer and Death Attack is worthless against random encounters. Unless you are playing solo and you are expected to find your own adventure seeds (are you playing assassin's creed?) they won't come into play often enough to outbalance other means of murdering your opponents.
Have a list of helpfulness anyway.
FeatsCraven (CoRuin): +ECL on SA.
Ability Focus: +2 to your Death Attack's save DC.
Aleval School(DotU): -1d6 SA to impose a -2 penalty to one save for one round.
ItemsBracers of the Hunter (SoX): +1d6 SA, +5 hide & +2 initative.
Rogue's Vest (MiC): +1d6 SA, +2 hide/move/reflex.
Murderer's Gloves (?): 3/day swift action, one round invisibily after SAing.
Umbral Awn or Custom Legacy (ToB/WoL): +3d6 SA.
Crystal of True Death (MiC): can SA undead.
Deathstrike Bracers(MiC): SA anything 3/day.
SpellsGrave Strike (SpC): can SA undead.
Golem Strike (SpC?): can SA golems.
Hunter's Eye (PHBII): +<cl/3>d6 SA, claim a cleric using anyspell made the wand for +6d6
Other Noteable StuffMantle of the Predator (MiC, item): +1d6 SS on melee only, +5 hide/move.
Shadow Veil (MiC, item): while in shadows, gain concealment against stuff that does not use light to find you.
Ring of Darkhidden (MiC, item): darkvision cannot see you.
Darkstalker (LoM, feat): blindsense, blindsight, scent, or tremorsense still has to roll to find you, flank creatures with all around vision.
Assassins Stance (ToB): 3rd level shadow hand stance, grants +2d6 SA.