Ahhh yes! Thousand Sons! I'm acually starting my army in a few days as I find them to be extremely strong and I just love the Psykers! You Eldar Players all say "Star Cannons." I agree that they are effective, but with two wounds, you would be able to take out one, or just wound one, no big deal. I think Pikachu suggested Banshees, well, I say that banshees suck vs normal marines, so how are they going to do any better against marines that have 2 wounds? Sorcerers are great, my favourite power right now is wind of Chaos: Go up to anything, flamer template, anything TOUCHES(not covered) by it dies on 4+!!!
They can also give more close combat effectivnes than an aspiring champion with better SW BS and Iniative! My tactic would be to have possessed ready to counter attack with maybe deamons going up the sides, flanking and dreads there to give out some heavy firepower along with a predator! They are also probably the cheapest army to buy!