The top ten general feats from PHB only (too many "munchy" feats from splat books - ie spellcasting prodigy)
1. Improved initiative
To go first is to have your opponent flat footed, or to ready an action agaist him if he is a spell caster. Can't say enough about going first. No Prerequisites.
2. Blindfight
In a world where there is magical darkness, regualr darkenss, invisibility, and blur/displacement effects this feat is essential. Defeat sneak attack good. No Prereqs.
3. Iron Will
The only one with a 1/2 way decent will save is the Monk, Paladin, or the Cleric [Druid]. That leaves an awful lot of classes waiting to to held, charmed, slept. No prereqs.
4. Point blank shot
+1 to hit AND dmage? For ANY ranged weapon within 30'? Even spells? Extra damage = extra good. AND it's a gateway feat. and it has no Prereqs.
5. Combat reflexes
If you are using the splat books, this is a must have for expert tactician (which is broken and wrong). If you are not, most assume you want to have a reach weapon to make this useful -you do not. Instead, all you need is a +1 dex and you can make more AoO's if/when they occur. As if that was not enough, you can make AoO's even when you are flat footed. No prereqs.
6. Quickdraw
Define a weapon? If I pull out oil to throw at an enemy, is that a weapon? How about a wand that delivers touch attacks? Since all those apply as 'weapons' IMC, this is a must have feat for everyone.
7. Great Fortitude
Lesser value than Iron Will, but Polymorph Other and Slay Living are both Fort save insta kills. Poison is everywhere as well (no, not the band)
8. Improved unarmed strike
I always threaten, even when unarmed. No prereqs. I can grapple as a result of an AoO. Or trip. Or disarm. You get the picture.
9. Spring attack
For anyone with more than a 20' move, this sure is great. For those barbarian's and monks out there, it is really special. It is also special to walk right through a huge dragons threatened area, and not provokve an AoO and get swallowed. Lot's of Pre reqs. Bummer.
10. Improved critical
The potential for double or more damage pulls your hoop out of the fire more times than you would believe. No feat pre-reqs. Appears at the bottom of the list becasue +8 BAB pre req means only fighter-types and cleric-types can even consider it, which is a shame.