A4 vs Celeron

Either is fine, the A4 will have slightly better iGPU but its less than half the potency seen on the A8's and A10's its also a dual core which is not the best x86 processor but its more than enough. Where AMD may edge it here is low cost A75 or A85 boards look nicer and have better build quality over low cost Intel boards.
 
movie watching i would say either cpu would handle the processing, but as said the A4 has a stronger igpu than intel hd graphics and would handle the graphics processing better, and the fact that current gen celerons run at around 2.6ghz around the A4s price range and its 3.4ghz