Gotta agree with DougofTheAbaci: You buy cheap, you will get cheap. Sure the $500 - $700 laptop may seem like a good deal at the time, with minimal impact on your pocket, it is more likely to be made with cheaper components with a potentially higher propensity to break and is probably made with components more likely to be obsoleted earlier. Investing earlier on in a bit more RAM, a slightly better processor and a larger hard-drive will give you a a couple more years out of your computer, and investing a little more in higher grade components will reduce the likelihood of immediate component failures. Toss in the fact that some computers, like Lenovo, are manufactured to higher specification, and you realize that a slightly higher investment earlier will benefit you later. 4 years ago, I purchased my current Lenovo X200. I paid a little more for the water-channeling and water proof keyboard, crash resistant housing and detection sensor around the hard drive, and what, at the time, constituted a thinner profile). Today, the hard-drive is a bit small for purposes as a full time computer, I cannot upgrade the RAM past 3.5 GB due to BIOS conflicts and the processor is a bit on the slow side, but the computer still functions excellently, has never had a major problem and is still my full time field computer.
Incidentally (to the OP), a lot of the problems you may face with a laptop can be fixed on your own with a little bit of know-how. From your opening post, you mention three laptops and a total of 5 problems: 3 hard-drive failures, 1 OS corruption and an Optical Drive that failed. All three issues could have been resolved. A little bit of prior preparation would have saved you from the issue with the OS corruption. First thing I do when I get a new laptop is set up an initial factory restore point or a restore disc specifically so I can get the computer to return to factory stock and start from scratch again. I also keep a copy of the OS I use on Disc so I can reinstall it from scratch if restoring doesn't work and download all the drivers for my specific computer from the manufacturer on day one (as long as your computer has a service tag on it with a computer specific number, you can go to the manufacturer's website and get the specific component drivers for your computer in one place). Hard drive failure will require you as a consumer to buy a new hard drive and reinstall everything, but it's not too much different from the first scenario except for one bit of hardware you need to replace - and most laptops these days, make the hard drive and RAM the two easiest bits of the laptop to access and replace. Of your 5 issues, the hardest to deal with would be the failed Optical drive, but you can either work around it as you did, or get a replacement part. You said it happened 10 months into owning the computer - I'm actually surprised that you couldn't get a replacement under warranty.
To answer the topic question - no, I'm not going to give up on computers in general. I have had specific problems with computer components, and in one case, really had problems with one entire computer (not mine - my sister's), but in those cases, I give up on a specific brand of component or that specific model of computer only.