Boosts

These are simple percentages that make your character hit harder, better, faster, stronger, or gain more Gold/Glory. They are not affected by scaling, and do not have any caps.

• Action Point Gain : multiplies your gain of Action Points (required for your Daily Power) by (1 + Action Point Gain)

• Recharge Speed : divides the recharge times of your at-will and encounter powers by (1 + Recharge Speed)

• Movement Speed : multiplies your unmounted speed by (1 + Movement Speed)

• Stamina Regeneration : multiplies your Stamina Regeneration by (1 + Movement Speed)

• Magical Damage Boost : multiplies the damage of your magical powers by (1 + Power Percent)

• Physical Damage Boost : multiplies the damage of your physical powers by (1 + Power Percent)

• Gold Bonus : multiplies the gold/silver/copper pieces you loot (doesn't work when selling) by (1 + Gold Bonus)

• Glory Bonus : multiplies the Glory (reward from Player vs Player content) you gain by (1 + Glory Bonus)

While Action Point Gain is nice for everyone, it is especially important for healers and tanks, to be able to mitigate damage when an emergency situation arises.

Recharge Speed is good for classes which have long cooldowns.

Magical and Physical Damage Boosts improve the damage of your powers depending on the type of damage they deal. Unfortunately, it's not always written properly in the game.

Stamina Regeneration lets you use your Tactical power more often. It's especially important for Tanks, so that they can mitigate damage.

Movement Speed is obviously great for everyone.

On the other hand, Gold/Glory bonuses are not so great, though they can have niche uses.