Assists

Partner Assist

Fireball (Hadoken)

This is a very useful assist because you can use it as a projectile if you wish, due to its fast travel speed.  You can also use it to extend combos as it does a good amount of stun and keeps the opponent on the ground. 

Variable Counter

Dragon Punch (Shoryuken)

This variable counter performs what you would expect it to.  It is easy to follow-up.

Variable Combination

Hyper Fireball (Shinku Hadouken)

Shinkuu Hadouken actually isn't that great in VHC's because it adds a lot to the damage scaling. It is very useful for Delayed Hyper combos though.