Accommodation options near conference venue:
The St. Regis Saadiyat Island Resort
368e per night
Hala Arjaan by Rotana Abu Dhabi
125e per night
Ramada Downtown Abu Dhabi
78e per night
Southern Sun Abu Dhabi
103e per night
Courtyard by Marriott World Trade Center, Abu Dhabi
132e per night
The best transportation mode in Abu Dhabi is taxi. Even though there is public transportation and it is very cheap, most people use taxis because they are not that expensive.
To get from the airport, there exists a public transportation bus, you can find the details on Abu Dhabi airport website under: http://www.abudhabiairport.ae/english/to-and-from-the-airport/information/public-transport.aspx (Service A1 which ends up near Abu Dhabi mall which is very near to Ramada, Southern Sun and Hala Arjaan hotels). Please note there that NYU Abu Dhabi mentioned there on the website is the old location and not the new one. The cost is only 4 AED (about 1 Euro). In case of a taxi, it should be around 100 AED (about 25 Euros) http://www.abudhabiairport.ae/english/to-and-from-the-airport/services/taxis.aspx.
For the transportation between the hotels and NYU AD, the best way is again to use taxis. It should be around 20 - 30 AED (6 - 7 Euros).