Battle against Tyranids, what should I bring?

[Raven Angel]

Fighting nids with SMs is not often a game of maneuver unless you face a nidzilla list. Horde armies are best crushed with massed firepower. Also don't forget that Hurricane bolters will benefit from the Standard of Devastation rule as the are 3 twinlinked boltguns. Technically storm bolters, heavy bolters and pistols should also but the rule is a bit ambiguous. Devastators and tac squads, operating around a Crusader will provide alot of firepower especially with the standard.

[Storm Dragons 3rd Company]

This is only an observation and it requires you be willing to waste a unit. In my last game against 'nyds, I shot my anti-tank at the MCs which is obviously what you intend to do here and killed the tervigon. He still had two 20 bug squads of hormagaunts each in a long double line advancing on my right flank at my firebase. I needed that firebase to shoot at the MCs next turn, not be fighting off the hormagaunts, so I needed to delay the advancing 'gaunts for a turn or two. So I moved an assault unit up along the right table edge to park it on the flank of the two hormagaunt units and then disorderly charged them. I expected to die in a turn or two but delay the bugs; what I got was an unexpected benefit.

 

First, by assaulting the extreme flank, I prevented him from consolidating with all his bugs into the melee and overwhelming me with his sheer number of attacks. Second he had his synapse creatures in the center (warriors I think) and on the left (zoanthropes) (the tervigon being dead and all). When I assaulted the flank of his 'gaunts, their mandatory consolidation pulled them out of synapse. At the bottom of the turn after i assaulted, I was down to one model in that unit, having done some damage, and then got lucky with my saves and ended up winning the combat by 1 wound. Being out of synapse, he had to morale check, lost twice and I caught and destroyed both units. The point is that you should always try to keep an eye on his synapse deployment and see if you have any way to either force him to move out of synapse or to force him to have to choose whether or not to assault or stay in synapse. It won't help in all battles, but when you can pull it off it's great.

[Nightmare84]

When I play a friends nids. I keep a dread in my fire base for the sure to be spored doom...

Nothing ruins doom like a dread to the face. As long as it didn't score enough wounds when it drops. Doom is useless and the dread just needs to sneak 1 wound through for ID