Always take STSF. That leaves you with 1 legacy choice. I'm looking at Cry of Thunder, Space, Landslide, and maybe Soul if you're uncomfortable with timing Cry (Cry is better if you have skillz).

If taking Sword primary:

Sword/dagger Landslide: great bleed + maledicts, unpreventable lag, 1-round initiate/redirect/damage/maledict move in artery, silent retrievals. Swords cover the melee side.
Sword/axe Cry: pincer lag, disembowel finisher, swords melee, Cry to fish for sudden bursts of damage along with STSF (i.e. even if they're half hp, a well-timed Cry-pincer-cutoff-disembowel can kill them).
Sword/axe Space (if drow, since drow have 24 dex): same advantages as sword/axe, and take Ambidextrous Disarmer. Basically forces a disarmed enemy to flee, or eat unblockable hits.
Sword/whip Space (if drow): whips disarm well (both offhand and mainhand). Lash is very reliable. Entwine. Eyejab is very reliable with high dex.
Sword/whip Cry: also good, but more for the post-entwine switch-to-swords and Cry tactic. I played a dark-elf warmaster once with this combo, it worked well.

If taking Dagger primary:

Dagger/axe Cry
Dagger/whip Cry/Space
Dagger/mace: make sure to take Skullcrusher.