The Tyranids can be fielded in lots of different ways. They can be upgraded to have a lot of shooting or downgraded to function as a true swarm. They can field a large number of monstrous creatures creating the so-called "Nidzilla" list. They are all quick and tough, forcing the enemy to be on the ball from turn one.
Here is the Battleforce:
3 Tyranid Warriors
3 Ripper Swarms
This gives you a decent swarm for $110, but has fewer weapon options than buying the individual boxes. This will run you $130 but the model count will be lower.
- The first thing to get will likely be a Hive Tyrant and some Tyrant Guard. He is a brutal creature and teh guard will protect him from sniping.
- Carnifexes are your shock troopers and will ruin your opponent's day.
- Genestealers can be devastating. Even if only a handful get into the lines, there will be few troops who can go toe to toe with them. Even terminators quake in fear.
- Bulk out your basic troops. If it doesn't look like a swarm you may be doing it wrong.
This army can be tailored like no other to go against an enemy list. Unfortunately, all those upgrades cost points. When spending points on something, ask yourself if another unit of Genestealers or a hulking big Carnifex wouldn't be better.Keep your army together and give your enemy too much to shoot at.