As a technician, I almost always recommend people against big box stores for desktops. They tend to use cheap parts, and I've seen a lot of desktops with problems after only a couple of years. I had one who had a machine fail at 4 months old. If you want to go to walmart or best buy, it's up to you. I can tell you if you go to microcenter, just looking up on their website, you can do a 2 year accidental warranty for 120 bucks extra on a 300 dollar laptop. To give you an idea. Also, whenever I've dealt with microcenter on parts, no middle man, I take stuff directly back to them, and they just take care of it.
You are more than welcome to go to best buy or walmart if you want, keep in mind though, you have any problems, you are likely going to have to send the machine back in. Or at best buy, you get the geek squad looking at it most likely. No offense to anyone, but I'm not trusting my pc to geek squad. I went to a best buy store once looking for work once when I was going to lose a job due to the economy. I have a bachelor's of science degree of communications(networking), had 2.5 years experience at the time, and was Apple certified. The guys at best buy didn't want to even call me back. But I think it had something to do with the fact the supervisor was younger than I am, and we were talking about how do you do this or that, and I said why don't you just do it this way, it would be easier. I think that possibly I initimidated him and maybe he was afraid that later I would get his job. But that tells me they want to hire high school kids that they can teach a few basic skills, teach to use a rescue cd, and pay them just above minimum wage. Not that there aren't good technicians there, but personally, I used to rebuild mac laptops a lot, I do custom builds, changed a screen in my own machine, modded it to have better cooling, put a new hard drive in it. I used to work for a school system doing their hardware repairs, corporate environment with servers. I just really would not want to trust my machine to geek squad. If they serviced my machine, I'd probably want to look to be sure it was right. More than likely though, I'd just do my own work.
I digress, most people don't know about brands like acer and asus sometimes. But what they don't know, asus has been one of the most reputable pc parts manufacturers for years. Acer is a great value brand, very little trouble with their laptops. Either one of those is a fine laptop. Don't get me wrong, Dell is decent, their business class stuff is top notch usually. Consumer grade stuff though, like I said, acer is what I recommend. I've only had to service ONE acer for hardware in the last two years. HP's, I have a hard time recommending them. I know they probably make great machines now, but a few years ago, there were a lot of nvidia gpu's being put into laptops, it seems like hp and compaq were what I saw most of and heard most of, having dead boards due to the graphics chips overheating. I know my acer has the same type of chip, and I had to mess with it's cooling system to get things cooler until I was happy with it.