I do home audio (both 2 channel and HT) as a daily gig... usually, higher-end stuff than this (Marantz, NAD, PS Audio, Martin-Logan, etc). But, that said, of those 4 options, the Onkyo would be the best performer, IME. If you decide you don't like the speakers later (which many people find to be the weak link of all these "all in one" systems), at least you'll have a good amp/receiver to work with.
I'd be inclined to stay away from the LG system. You know that LG is actually just GoldStar, under a new name, right? They make OK cell phones and kitchen appliances... but I've never been impressed with their audio electronics...
Regards,
Gordon.