The build I have had the most fun with is Twin Fang Strike Assassin. Unfortunately, the synergies never worked as intended and was later removed.
What I found most fun about this build was the difficulty it posed. The normal claw sin back then was a lot stronger due to claw block. But this build had the speed you wanted and the damage you needed, with basically 0 survivability, which made all actions depend on your actual skill, making enemies flee, or stunning them at the right time, using Vampiric Icon to constantly leech life and so on. It took all I had just to kill a few souls in Duncraig and that was really fun. Plus, it profited a lot from using a honorific weapon, which I don't think many builds can claim tbh.