Druid Feats

[Rasman]

I've decided to write up a 13th level druid for a future Pathfinder Core Only game, but I'm having trouble with the feat selection.

Natural Spell seems like the only no brainer. Planning on being melee focused because I don't think anyone else wants to be the I'M IN HIS FACE I HIT HIM HARD AND MAKE IT ANGRY guy, so Power Attack seems staple, but other than that, I'm not really sure what I should be picking up. I've considered

Power Attack
Combat Expertise
Improved Trip
Greater Trip
Cleave
Natural Spell
Spell Focus (Conjuration)
Augment Summoning

The last two most because PF druids are just good summoners and if I'm going to be summoning a lot, I might as well make it bad ass.

I read that working towards Heavy Armor Proficiency was worth it in the long run so I could wear Iron Wood Heavy Plate or something like that, but I'm not sure if burning a feat is worth it for the benefit, not to mention the cost...

My only restrictions are that feats MUST come from a Pathfinder Source book, so it can come from the Pathfinder splats, but no 3.5 material.

[Greenish]

I've decided to write up a 13th level druid for a future Pathfinder Core Only game
…
My only restrictions are that feats MUST come from a Pathfinder Source book, so it can come from the Pathfinder splats,

Does not compute.

[Thrice Dead Cat]

Power Attack generally doesn't mesh well with natural attacks, as you can't get the 2 for 1 return.

For feats, if human, I'd go
1st: Spell Focus: Conjuration
H: Augment Summon
3rd: Power Attack or Multiattack. I'd go more with multiattack
6th: Natural Spell
9th: Extend Spell
12th: Improved Natural Attack (Claws, most likely)
15th: Improved Initiative
18th: Quicken Spell

[Rasman]

Does not compute.

I know...contradictions are contradictory

Power Attack generally doesn't mesh well with natural attacks, as you can't get the 2 for 1 return.

For feats, if human, I'd go
1st: Spell Focus: Conjuration
H: Augment Summon
3rd: Power Attack or Multiattack. I'd go more with multiattack
6th: Natural Spell
9th: Extend Spell
12th: Improved Natural Attack (Claws, most likely)
15th: Improved Initiative
18th: Quicken Spell

don't know how I missed Multiattack...just wasn't looking at Monster Feats, dur...druid...

I was mostly thinking Power Attack for other feats, or because of bad AC Combat Expertise, also to get to Greater Trip. I wasn't sure how Imp Nat Attack was going to work, since I don't, technically, have a Natural Natural Attack, but that would probably work well anyway. Entend Spell isn't bad, but I'm not terribly sure how. Quickened Spell just seems kind of Gimp though, I get that you technically can cast 2 spells in one round, but eating a spell slot 4 levels higher seems steep. I'll probably take the Extend Spell suggestion though, seems pretty solid just for the +1 level.