What feats would you associate with a professional boxer?

[Vidmaster7]

Unarmed strike of course
Probably improved feint, dodge, step-up
what else you guys got?

[Texas Snyper]

Mobility, to pair with the Dodge: to be able to float like butterflies.
Power Attack: to sting like bees.
Spring Attack: they tend to be very mobile and move in for a strike when they see an opening.

[I'm Hiding In Your Closet]

Stunning Fist!

Possibly also Punishing Kick and Vicious Stomp, depending on what style of "boxing" one has in mind.

Toughness/Endurance, especially if you really want to be like Mohammed Ali and "rope a dope."

Alternatively, you could be a pale shadow of Dhalsim and Lunge!

[Java Man]

Jabbing or pummeling style. Or both. Certainly toughness. Weapon focus and specialization in unarmed strike.

[I'm Hiding In Your Closet]

Combat Expertise and several of the "Improved/Greater [combat maneuver]" feats - once again, depending largely on the style of "boxing"

[Vidmaster7]

Was thinking traditional boxing instead of MMA

Good stuff so far.

[Iff]

Outslug Style, and its followup feats.

[Azullius Koujou]

by name alone I'd go for jabbing style and probably also dodge as the first to come to mind.
Anticipate dodge, Circling Mongoose, counter reflexes, false opening, sidestep, improved sidestep, counterpunch.

I'd also relate to a boxer

[Louise Bishop]

Jabbing Style
Circling Mongoose and Outslug Style
Dodge, Mobility, Spring attack
Combat Reflexes
Counter Punch
Step up, Following Step, Step up and Strike
Lunge
Stunning Fist

Some dirty boxing:
Improved Reposition or Drag (clench fighting and throwing um into a corner or ropes)
Strike back
Befuddling Strike

There is a feat that let's you do 2 styles at once. Or you can dip MoMS monk for fuse style, wisdom to AC and stunning fist.

[Blymurkla]

Barroom brawler in order to adapt your tactics to suit different opponents (although I suppose levels in Brawler would be a good way to represent a professional boxer, making it rather superfluous).

[tonyz]

Weapon Focus: fist
Greater Weapon Focus: fist
Combat Expertise (you fight in no armor, you want max AC protection by blocking)
Power Attack
Weapon Specialization: fist
Greater Weapon Specialization: fist