Granted that my rogue group isn't real high, I have found S&D to be a waste of energy, as even elites don't seem to last long enough to be worthwhile. Maybe I am confused but I remember having a fast off hand weapon for poisons was good, but I thought they made the poison procs/minute so speed wasn't such a factor. I like to give one rogue crippling poison, and one mind-numbing, and instant (possibly wounding) the rest. I really don't need the first two in all situations, but that's what I do anyway. Mobs have too little life to bother with deadly for the most part IMO.
I don't have my macros handy but I love having backstab in, because the mob always has his back to at least one rogue. That means daggers instead of swords or maces. My dwarven team uses dagger/mace until I find better daggers or fist weapons get some better items. YMMV
Something like:
/castsequence [targetwhatever] reset=yaddayadda backstab,
/castsequence [targetwhatever] reset=yaddayadda Sinister Strike, Eviscerate

Note: This is from memory of a team I have not played in a long time (since WotLK), now I've got the urge again. Altitis strike!