What is the best standard and new hotel in Bangkok Sukumvit soi 7 - soi 19 area?

My budget is around 4000 bath/night maximum. I will stay with my wife and 2 child whose age is around 3years and 4 years. We prefer to stay in a suite room.

- Sofitel Residence Asoke : Sukhumvit soi 19

Pls go to website : www.asiarooms.com/thailand/bangkok/sukhumvit-area.html?cpg=2&sort=rates&extraSortRate=2000-4000%20THB&type=asc&extraSortRate=2000-4000%20THB

Here's a pretty good map and list that shows the hotels and some serviced apartments in the area you mention. Unfortunately, prices have risen quite a bit over the last year or two and the best hotels are well above your stated price range, but there should be plenty to choose from for around 4,000 baht. Check out Centre Point on Soi 10, some friends of mine stayed recently at the Adelphi Suites on Soi 8, a brand new property with very nice suites in your price range:
http://www.hoteltravel.com/thailand/bangkok/sukhumvit_map.htm

There Sukhumvit S15 hotel, its a new boutique hotel that cost about $100 USD/night, it on the main road and about a 2 min walk to the BTS station and Robinson.

How about "S15 Sukhumvit hotel"? it's B3767 for Junior Suite, and B4788 for S15 suite.

Location is perfect, especially if you want to be in and around the center of activities. Hotel is located just on the main Sukhumvit road, between Asoke and Nana. So it's easy to move around. Room is really impressive and comfortable. Have a nice trip.