I’m on USWest. I’m currently working on finishing off a Maul Barbarian (currently level 67 in Act II Hell Difficulty).
My $0.02 regarding Assassins:
IMO, the only traps worth having across all three difficulties are Lightning Sentry and Death Sentry. Death Sentry is particularly nice due to the built in corpse explosion attack. All the traps are extremely mana-inefficient, though, and you could skip the Traps tree entirely and be none the worse for it. The traps are there to soften up a pack of monsters; don’t expect your traps to kill anything by themselves unless you’re extremely patient.
Most of the common Assassin tactics revolve around a divide-and-conquer strategy. Break up the mobs; blind them, chill/freeze them, knock them back with Dragon tail (Dragon Tail is a rather slow attack, though). Then use your superior speed to take out the monsters a few at a time. I’ve only had limited experience with Assassin builds. The ones I did make tended to focus on a high damage, quick attacks against single opponents (Tiger Strike + Burst Of Speed, with or without Dragon Claw) and moderate crowd mutilation attacks (usuall Phoenix Strike). Equipping a fast weapon and charging Phoenix Strike to drop Meteors in rapid succession can be very effective.
Shadow Master is extremely useful. Venom is not, since the poison implementation is currently flawed in patch version 1.09. Being a speed-orientated player in general, I used Burst Of Speed almost constantly.
Assassins can tank decently well, especially when outfitted with decent cold area-of-effect attack skills. I don’t have extensive experience in this area, though, since standing around trading blows is not my playing style. But I’ve seen it work on Assassins that were equipped with decent gear.