Best buffs I have ever run into are City of Heroes/Villains buffs.
And probably the best in that lot fall under Kinetics.
Siphon Power
Ranged, Foe -Damage, Team +Damage (basically, you hit a foe with this, their DMG drops, and all of your teamates around you get + DMG)
Siphon Speed
Ranged, Foe -Speed, Self +Speed, +Recharge
drop a Foe's speed dramatically to seriously up your own speed and recharge times
Speed Boost
Ranged, Ally +Speed, +Recharge, +Recovery, Resist Slow
CRACK!
This is what makes Kinetics Deffenders so damn popular. Massive boosts to spped, recharge time, and energy recharge!
Inertial Reduction
Point Blank Area of Effect, Allies +Jump
All any one near you gets a good boost to their jump height. Combine that with speed boost/siphon speed and you get Heroes on Crack!
Empathy also holds a very good buff:
Fortitude
Ally +Defense (All), +Damage, +Accuracy
basically make a single ally that much more badassed!
