You've used the Newb Combo. You feel guilty. You hear swears and insults. If there were only some similar and acceptable technique that took more skill.

Pro Combo

Although self-proclaimed Halo professionals would deny it, the grenade and battle rifle combination technique is very similar to using a plasma pistol and a battle rifle. Instead of shooting an opponent with a powered up plasma pistol, followed by a battle rifle shot to the head; throw a grenade near an opponent and follow it up with the same battle rifle shot to the face. Granted, accurately throwing a grenade is potentially far more difficult than simply connecting with a "heat-seeking" plasma burst. But the Pro with his grenade does have advantages over the Newb and his plasma. The pro combo can be more successful from a distance and more useful in tight spaces. You don't have to wait for a plasma pistol to power up and you don't have to switch your gun after you throw a grenade.

Bonus Tip!

The Pro Combo is a great last resort strategy if your opponent has more energy. Many near death experiences have resulted in kills.