This liteon is one of the most popular readers. With modified firmware, it is very fast (even without modified firmware it is pretty fast) and it is a pretty good reader.
The aopen 1608/1616 is a very good cd burner (2 sheep meaning it can read well enough to get past some of the tougher cd copy protections), and my personal experience at least, on average, it reads disks that none of my other drives can read. For me at least, it has proven to be a very solid dvd reader and it is resonably fast. While it is a dvd burner, its dvd burning sucks with a big capital S.
the aopen 1648 has been claimed to be an exelent dvd rom too. I don't think they are easily avalable in the US though I still see some online shops in other countries carrying them. Should you run across one, they are suposed to be very good. Here is a thread about them.
The benq 1640 is not only a very good dvd burner, it is also a fast and good dvd reader. there are some people still activlly seeking these drives even though new models are avalable. Thier avalability is limited though rebadges (that drive with someone elses name on it) are still avalable, and there are a few 1640s still floating around. The newer benq drives 1650/1655 seem to be very good burners. I would suspect that they are good readers like the previous benq's, but I cannot say for sure (I just don't know either way). they certainlly merit looking into though. Beware the benq dq60. It is a piece of crap. The newest liteon models are suposed to be good readers as well as good writers. They are very good error scanning drives (as are the benq's). I'm not super farmiliar with the particular models of the newest liteons, but liteons have traditionally been very good readers and very good scanners, and I have heard more than one time that the newer models are very good burners too.
Personally, since your lg cannot do error scanning, I think I would tend towards a benq or liteon burner. either should serve very well as a reader as well as providing decent scanning ability. Being able to scan is a very important part of getting good burns.