Currently i am using acer aspire 4736z with 2 gb RAm, and honestly i am super happy with accer, till now no problem and battery back up till now more then 2 hours and for your kind info i am using this laptop more then 3 years, and if you looking for some quality then you should go with acer, Check this out
Acer Aspire AS5560G-8356G75Mnkk 15.6" LED Notebook
it has AMD A-Series A8-3500M 1.50 GHz - Black - 1366 x 768 WXGA Display - 6 GB RAM - 750 GB HDD - DVD-Writer - AMD Radeon HD 6650M Graphics Card - Bluetooth - Webcam - Genuine Windows 7 Home Premium - HDMI
i guess my info will help you the right laptop for you. Thanks.