I'll start off,
- Arcane Smithing (Smithing), I ended up increasing my enchanting skill, so there wasn't much point in improving pre-enchanted items.
- Paralyzing Strike (One-Handed), backwards power attacks are hard to land unless your enemy is charging and 25% is just too low a chance at paralysis to bother using it, besides shield charge is a more reliable method of taking an enemy out of the fight. If you aren't going to use a shield I could see the appeal though.
- Shadow Warrior (Stealth), It's not bad, per se, but I can only think of two occasions the invisibilty has helped me and both times I was trying to assassinate an oponent I could have meleed anyway.

I'll have to test that later when I get home.