This has gotten me thinking about what the BEST feats are. I know that what qualifies for "best" will change from build to build, but I think there are a few we can all agree on being indispensable for a given character.
My votes are:
Natural Spell (any wildshaping Druid who doesn't take this is (a) trying to be bad or (b) not paying attention. or (c) a complete noob)
Persistent Spell (not every spellcaster takes this, but look at how much time and effort is put into optimizing builds around it)
Improved Initiative (win initiative = win combat)
Practiced Spellcaster/Manifester (for any build that loses CLs or MLs)
Anything else indispensable?
Adaptive Style (for swordsages)
Darkstalker (for sneaks)
Entangling Exhalation (for anything that breathes something)
Font of Inspiration (for factoti)
Leadership + variants (for anyone)
Mindsight (for anyone with with telepathy)
Power Attack (for two-handed melee characters)