I will do this specific to my school - what each chapter has taught me, or something that I admire about each chapter.
Alpha Chi Omega: I like the fact that the original name was "Alpha Kai Omega" for Alpha and Omega. I think that's really cool and i like that it was later renamed to fit better with the rest of NPC sororities. Alpha Chis on my campus are very involved on Panhel exec and work so hard for all 12 sororities not just their own chapter!
Alpha Delta Pi: On my campus, ADPi is the newest sorority and they have been working so hard to establish themselves on the campus. Not only are they beginning to make a name for themselves, but they are super active on Panhel exec and ALWAYS have two members on Panhel exec (the maximum amount any one chapter may have!)
Alpha Phi: Their national HQ is located roughly two blocks from the Alpha Phi house on my campus, so its cool that they really do get a lot of support from their nationals!
Chi Omega: This is one of the smaller chapters on my campus, but every Chi Omega I know genuinely loves their organization. Their house mom is one of the nicest women I have ever met. I also love that the owl, a symbol of wisdom, is one of their symbols.
Delta Delta Delta: These girls celebrate diversity within their members which I really admire - I wish my chapter was that diverse.
Delta Gamma: These girls have amazing spirit - half the campus knows Delta Gamma songs because they sing them loud and often! Their Anchor Splash is a really well-run philanthropy that raises tons of money each year!
Delta Zeta: This is a smaller chapter but it has the closest-knit sisterhood I have ever seen. These women really understand the meaning of the word sister and are so supportive of each other its amazing. I also love the colors pink and green. Also, DZ's on my campus are incredibly involved on Panhel exec, always occupying two positions.
Gamma Phi Beta: This organization is full of dynamic and talented girls. These are the girls that, more than any other organization, occupy leadership positions all over campus - in student government, in campus-wide philanthropies, in the newspaper, etc. They contribute so much to our campus with all of their hard work. Also, their Lip Synch contest for charity is hilarious to watch!
Kappa Alpha Theta: These girls are really on the ball about getting good PR for the greek system. They really emphasize, both within our chapter and amongst all 12 sororities, that the actions of a member reflect upon the organization. They are really good about risk management and about enforcing Panhel rules (ie, Code of Ethics, no drinking in letters, etc). If all chapters were like this I think Greeks would have much less of an image problem!
Kappa Delta: These girls exemplify what it means to be a sorority. They have tremendous respect for their ritual, for their organization, and for the values upon which their organization was founded. Of all the chapters I have ever seen, this is the only chapter I see where I think that if their founders could see them now, they would be incredibly proud of the tradition these girls carry out. They are also super-committed to campus activities and always have amazing homecoming floats and the like.
Kappa Kappa Gamma: I really admire the way Kappa emphasizes the connection between the current collegians and the alumnae. I think in most organizations, the alumnae connection is overlooked, whereas Kappa pays a lot of attention to its history, both as a national organization and as an individual chapter. I love how they have old alumnae come and talk to the chapter about what it was like to be a Kappa years ago.
Pi Beta Phi: I'm a Pi Phi so obviously I am going to say good things about my chapter!

I really admire my chapter for our participation in campus philanthropy events - we are the philanthropy queens in that we participate in and win more philanthropy events than anyone else. I also admire our philanthropy, Links to Literacy - my chapter works with children who read below grade level to help them increase their literacy skills which I think is wonderful.