I personally use sinister strike alot, despite not being a combat build. With my playstyle, I prefer high damage in my main with high DPS in my off.
But let me make this real easy for you, in 4 numbered steps:
1) Gain 2 levels to 27, find a level 30+ rogue friend, and go to Gnomeregen.
2) Go right in to the big room, fall down to the bottom, heal up, and kill the Viscious Fallout.
3) Loot Toxic Revenger.
4) Don't worry about mainhand for a long, long time. :)
TR is statistically a 25% drop. Took me 8 kills though. Worth every silver spend on repairs and every second in that hell hole of an instance. I can't recommend this blade enough.
Lexington of Titan
Taru DRG; Retired
Lexington of Stormrage
Orcish Rogue and leader of Fatima War Prophecy