Nominaly Black Templars only have one single troops' choice, but depending on their role and equippement two different types can be destinguished.

Black Templars Squad - Close Combate

The - probably - most typical Black Templars unit. All models are equipped with close combat weapons, plus a power weapon or power fist and a special weapon. The largest drawback this unit faces is the lack of a veteran sergeant. Not so much because of his improved leadership, but because of his extra attack. While many people see the ability to give a basic trooper a power weapon as a big advantage, it also means you get one attack less with it, which makes much more of a difference than many people think. It also forces you to take either a power weapon or a heavy weapon, which in turn brings out the Black Templars' character as an army.

Close combat squads should always use a transport to get into close combat as fast as possible. While this will become much more difficult in 4th ed, a rhino is still the fastest way to get your troops to the enemy. And don't forget your crusader: It can hold up to 15 space marines, enableing you to take 10 paladins, 4 neophytes, add a character and still mount them in a transport. Large numbers make up for the lack of a veteran sergeant and will probably become even more important in 4th ed. Being able to take more than 10 men per squad is a big advantage for Black Templars that is often over looked - use it to your advantage. Black Templars squads that are equipped for close combat should always get frag grenades, unless you plan to transport them with a land raider crusader.

Black Templars Squad - Fire Support

Due to their character as a close combat orientadet space marine chapter the Black Templars usually have less fire power than other space marine armies, and their fire support squads don't fight as well in close combat due to their lack of a veteran sergeant. But they can take plasma cannons. Sure, plasma can overheat, but the plasma cannon is still the most versatile heavy weapon in the game. It is excellent against heavily armoured troops, extremely effective against light, open topped vehicles and can even take on high toughness creatures or vehicles with medium armour.

These squads will have to make up for your lack of devestator squads. I prefer small squads of five or six (sometimes with a neophyte for fluff reasons) in a razorback. That way I get two heavy weapons, the razorback usually being armed with twin linked lascannons. That way I have a very versatile armoury against vehicles and heavily armoured troops, while my close combat units must take on larger groups of light infantry. The ratio of close combat and fire support squads is usually 2:1.

A variant of the fire support unit is a 10 men squad with close combat weapons and a heavy weapon. While the main focus of this unit is fire support, it can also take on smaller infantry units. It is well suited to hold flanks or as reinforcement.