I use my own variation on action points, and I apologize in advance if this has been discussed before. 1 action point can do the following:
* +3 to attack rolls, save rolls, skill rolls, ability check rolls, level checks, etc.
* Automatically gain initiative
* Deal MAX damage on a single attack
* Gain an additional follow up/single attack (melee/ranged)
* Recover a lost spell (1 AP = 1 spell level)
* Gain an additional per day usage, of some special ability/class feature/spell like ability (this includes things like additional cleric's turning ability)
On the topic of second wind: I don't use it, my players want hit points back, better have a cleric or a potion