What is the best way to get to Istanbul from east coast USA.

Depends on where you are actually starting. Turkish Air often has direct flights from Dulles to Istanbul.

Turkish Air is great. It has very reasonable prices.

Also recommend Turkish Air. Great economy class.

It depends on where you are flying from, the time frame, the criteria of "best." It can be duration, cost, number of layovers, departure time, arrival time, FF affiliation, layover airport, etc. You can examine options on your own using matrix.itasoftware.com to look at flights from different angles. Use time bar display option.

Within Turkey/Europe another option is Pegasus. Warning: they use the airport on the Asian side of Istanbul--much farther from the downtown sites (all pretty much clustered on the European side). If you use Pegasus, the bus to Taksim Square (central Istanbul) runs about once per hour.

Istanbul traffic is horrible. It is basically one big traffic jam all day.