A. West: The newer part, it also has a higher per capita income(on the order of $100,000-$120,000). Its schools are still a hotbed of drug activity due to the high preponderance of bored, rich kids, but heroin has fallen out of favor.
B. East: Considered by most Plano-ites, to be the "ghetto" section of Plano, the vast majority is still upper-middle class. It however lacks the number of shopping malls/ multiplexes/ etc. that have arose in the west side during the building boom that hit the DFW area in the 90's.
A city that is sometimes thought of as "all of America summarized into one city." In this city, there are at least 20 people from each region of the planet. The crime rate in Plano is usually minimal, however drug abuse occured often in the 90's. In the early 90's and late 80's Plano was a large town with few shopping centers and malls, until a building boom in the mid-90's occured.
Plano is often divided by young citizens, the West side and the East (also known as downtown Plano, or more crudely, the Ghetto- it is not very poor, however it isn't as new.) The West Side has more money per capita than the East side. East Planoites (usually of teenager age) describe West Planoites as snobby, rich bitches, spoiled, bored, and potheads. People from outside of Plano say such things about Plano, usually because they don't have anything better to do or they used to live there and got treated poorly.
Plano is also often known as unique or diverse. Most of the defintions of Plano on Urban Dictionary are hateful and poorly written, or completely opinionized. The best resource for info on Plano, historically and presently, is Wikipedia.
You got the minorities in the east who beat/shoot each other up.
You got the middle class mixture in the center of the city who is high on pot.
Then you've got the snobbily rich white kids in the west who are high on heroine.