How many teams in the NBA have a great center?
As long as by 'great' you mean a modern age center who is 6'10"+ plays 30+ minutes and gives you around a double-double.
Here are the teams who can feel great about their center:
Washington - Gortat
Chicago - Noah
Charlotte - Big Al
Atlanta - Horford (If you call him a center)
Detroit - Drummond
Orlando - Vucevic
Toronto - Valanciunas (should make jump from 11/9 to like a 17/11 this year)
San Antonio - Duncan
Houston - Howard
Memphis - Gasol
Minnesota - Pekovic
Sacramento - Cousins
How many have a good to very good center?
Portland - Robin Lopez (great if he could score 15 a game)
Brooklyn - Brook Lopez (great if ever healthy)
Detroit - Monroe (great if was even above average on D, but def more C than PF)
Golden State - Bogut (great if ever healthy)
New Orleans - Asik (great if he could hir FT's and score 15 a game)
Dallas - Chandler (great 2-3 years ago)
Utah - Kanter
Lakers - Pau Gasol (great 2-3 years ago)
Clippers - Jordan (great if he could hit FT's and score 15 a game)
Cleveland - Varejao
Miami - Bosh (if you call him a center, was great 2-3 years ago)
Indiana - Hibbert
Denver - McGee
How many teams have a below average or still unknown situation at center?
Boston - Faverani is a backup, Olynyk can't be projected (yet) as more than a 6th man who swings between PF and C
Philly - We have yet to see Noel play and Embiid will be out a year
Milwaukee - Pachulia is like a better Fav, only on the downside of his career. Sanders can be in the good to very good group if he gets his head on straight
Oklahoma City - Perk has been in serious decline for 2-3 years but Adams should quickly bump them up into having a good/very good center, we just don't know yet.
Phoenix - Len could be very good soon. Plumlee was actually an 8/8 guy in 24 minutes. No reason they won't be in the good/very good group this year.
Knicks - Amare sometimes plays the 5, horribly overpaid and washed up, Dalembert is old but can still defend a bit
I would trade Fav/Oly for every duo I just mentioned on the other four teams with poor center situations except for Milawaukee and New York. Therefore, the Celtics are the third worst team at the center position in the NBA. At least until the Lakers let Gasol walk.