I will go with Acer,we have 3 at the moment 2x17inch and 1x15inch screen they are not the best looking machine that would go to Sony but if you want a no frill's reliable laptop then Acer ticks my boxes.
Im surely go for acer, since i got one hp laptop last year and it just good outside but poor inside. Now acer already improved much compare to last 3 years and they also provide a good price and features. I'm using dell, but sometime use my sister's laptop acer.
whew... ACER is way to FAR from HP in terms of quality and reliability and ACER in the other hand is way cheaper than HP. If you want a kick-ass laptop go for HP.
If that were the only 2 options I would go with the acer. Just wondering.....Why don't you get a mac,if not a mac then get a toshiba.
Personally I wouldn't choose Acer, I can't really trust on their quality - of course it might be better nowadays if you don't buy the cheapest models.
I have used both HP and Acer and both are really good laptops. I would go for HP as a first option If you wish to go for a Dell laptop, go for one of the more expensive ones as the lower end prices give up after while.
If you're going to buy a notebook, consider the speed and Dell has the specs that suits your comfortability.