A lively place day and night with many low rise condos and a large choice of restaurants / shopping centers.
Everyone living in Bangkok knows Thonglor. This is one of the most popular place among thais and foreigners. What makes it so popular is the large choice of shopping centers, restaurants with outdoor terrace but also luxurious condominiums along this large road and hidden in the small sois all around. Many are looking for a condo there to buy or to rent so that they can enjoy all those facilities. Note that the nearby soi of Ekamai is also a good alternative if you cannot find or cannot afford a condo in Thonglor.
Many westerners and japanese love this area and all the luxurious condominiums available there. Low rise, High rise, fancy designs you will find condos for every taste! Thais of course also love the area and you can surely spot some actors / actress or successful businessmen / women living there.
However there are also some more affordable condominiums in there very popular with the middle class.
Thonglor road is a 4 lanes road that helps digesting the traffic most of the time. There are also as usual a lot of connected sois that help traveling avoiding traffic to join other parts of sukhumvit road.
Regarding other means of transportation, there is a BTS station at the intersection of Sukhumvit and Thonglor. On the other side of Thonglor, crossing Petchaburi road and then turning left to follow Kamphaeng Phet 7 will bring you to the airport express Ramkhamhaeng station.
One of the most popular chilling out place in Thonglor is J Avenue. But in fact there are now numerous shopping villages where you can find food to refill your condo and relax yourself. The good thing about Thonglor is that most places are also outdoor so you finally won't feel claustrophobic anymore.
J Avenue, Penny's Balcony (opposite J Avenue), Thonglor Town Center, M Place are just a few names of the many centers you will find. Many great restaurants of every kind, wine / beer tasting bars available everywhere!
Bangkok Hospital is located just across Petchaburi road and Samitivej Hospital is also directly reached from Thonglor soi 13, both of them are a good pick for international class services. You can also find directly on Thonglor Camilian Hospital.
Thonglor is a great place to hang out at night. You will find some fine bars and clubs where you will find people from all around Bangkok. Atmosphere in those places is mostly cozy, not disturbing the neighborhood and you will surely discover some nice concepts like HOBS (House of Beers) for belgium beer tasting. There are also very nice music bands to be found around there so keep your ears open!
Restaurants in the area are japanese, thai, european (many countries represented)... It would be useless to name them, I would rather recommend you walk there and try as there are a lot to be discovered. You may like the atmosphere of M Place or Penny's Balcony, J Avenue or Thonglor Town Center.