This post is silly. Brand doesn't matter? Hirarious. Keeping your devices on a charger all the time will make the Li-Ion battery's effectively immortal? Ridikulus.
I've fixed plenty of computers, both desktops and laptops. Many of them were Acer's and quite a few were Dells. The Compaq's were never repairable, and the HP's only sometimes so. But I've only ever had to fix one Toshiba (some of their earlier models had a problem with the display cable shorting out, simply replacing the damaged part fixed the issue).
Heck, just disassembling the things will give you a good idea of the build quality and the engineering put into them. Also, no, the manufacturers don't buy their designs from China. Acer might, since their stuff constantly breaks, but I highly doubt Toshiba or Dell do. Though Dell's used to break quite often in the earlier days, more recent designs have proven more resilient. The layout of the components is quite logical compared to an Acer. As for Compaq, my sister had one who's PCI-e bus failed. It was a common problem on all compaqs made that year which reared it's ugly head around the third year of consistent use. A year after the warranty went out.
That said, I'm still no fan of Dell. Toshiba's have proven to have the best track record for me, and I know many people who are satisfied customers of ASUS.
Also, you might want to take Apple products into account here. They are very much PC's in every sense of the word. They can run Windows and Linux just like every other laptop out there. And, like many other manufacturers, they design their products in-house and have them built in China. Apple is able to achieve such a high level of quality in spite of out-sourcing to China because, contrary to popular belief, China is capable of quite high levels of quality control. The only problem is, that unless you're a really big customer (like Apple), they won't care too much about your requests in regards to quality control.
Brand matters very much so because the quality control for each brand's products varies between brands. The core components may be the same, but the design of the PCB's and the choice in quality of passive and supportive active components makes a big difference.
If you want some evidence to back this up, take a look at some of Square Trade's observations of their 3rd party warranty business. In terms of how often problems occur in their products, and the general longevity of said products, Square Trade found out that Asus, Sony Vaio, Toshiba, and Apple were (in that order) the highest-quality brands their customers purchased.
If you want to be cheap and only pay $500 for your Core i7 laptop with 8GB of RAM and a 750GB HDD, go ahead. But don't expect it to last you more than three or four years at best. As for my friend who spent $4k on his Macbook Pro (personally I think that's a bit overkill, but I digress), he's basically gotten an entirely new laptop out of it thanks to Apple's wonderful warranty program. The only reason the parts on his laptop failed (motherboard, DVD drive, battery) was because he used the hell out of that thing. He's an IT guy, and at a couple points in time, he used the laptop as a temporary server during OS upgrades and migrations. He got the Laptop in 2008, so the warranty just went out last year, but he's been easier on it lately since he doesn't need to rely on it so much. Even so, he still uses it daily, and will likely continue to do so for another two years or so. 5-7 years for a $4000 laptop? Not bad at all. Though you could also spend $1200-$1500 on a really nice Asus and have it last nearly as long. Though the warranty program isn't anywhere near as good as Apples.
That's another thing. When you buy a laptop, you're also buying the service of the company who designed it. Now, you can either buy something from Acer and deal with their wonderful tech support who lives in India and barely speaks english, or you can buy something from Apple and deal with their tech support who lives in California and speaks english perfectly. Though I suppose it doesn't matter since "all brands are the same" and therefor their tech support is too. Hah.
As for batteries, it's a commonly accepted notion that over charging a Li-Ion/Li-Poly battery is just as bad as running it dry, The key to long battery life is charging consistently but in moderation. For phones, it's usually best to charge them over night. However, there's no sense in charging it while your at your desk at work, as that will merely stress the battery unnecessarily.
As for my suggestions in purchases, while I think Apple's laptops are a great investment if you can afford them, most people can't. My dad couldn't when he was shopping for a laptop for my sister (to replace the Compaq that crapped out), nor could he when he was shopping for one for my mother. In both cases, I helped him find very good Toshiba laptops that fit both of their needs. My sister's even has some really nice Harmon/Kardon speakers, which sound just as good as a Mac's. It's also got a Core i5, an Nvidia 430M GPU, and a 15" screen with a 1440x900 resolution. All for around $750-$800. My mom's is much more bare-bones with a Pentium class CPU (same 1st-gen Core i series though) and integrated graphics, but it has the same resolution screen, great battery life, and an eSATA port to boot. No fancy speakers though.
I guess what I'm trying to get at, is that while I agree that you needn't spend tons of money on a laptop, you should absolutely consider quality as a factor, and unless you only need something really simple for browsing the web and watching a few videos (with headphones), you should expect to spend between $750 and $900 for a good laptop with discrete graphics. Though you can get good-quality laptops that are less powerful for anywhere from $600-$700.