Feats Only: What's a feat worth?

So as this "feats only" RPG thing takes root in my mind, I'm forced to wonder what a feat is worth. My first inclination is to say something like "+1" or "+2". But it's more complex than that.

My basic idea for progression is this:
1st level: Gain 1 class feat, 1 racial feat, and 1 "misc" feat.
2nd level: Gain 1 class feat.
3rd level: Gain 1 racial feat.
4th level: Gain 1 misc feat.
5th level: Gain 1 class feat.
Etc.

So the answer to the question of "what's a feat worth" is "1 level".

So far, here's what I've got, with no play testing or data to back it up other than my thumb in the wind.

Pick 2:

• +1 bonus
• 1 divine spell
• 2 arcane spells
• +1 level of hit points
• Fill a prerequisite
• +1 die of damage

or

Pick 1:

• 3 arcane spells
• A special ability
• An additional attack
• +1 level of hit points (stepped up twice)

So a typical fighter feat may be something like "+1 to hit and +1d8 hit points". A typical wizard feat may look like "+1 to casting and +2 spells".