Hi,
I would say that your experience is typical. I am now on my fourth unit (I have to keep getting them replaced under warranty). This isn't so bad as within the EU you now have 2 years warranty on all items such as this as part of your statutory rights. I actually bought an AV440 and when it broke they no longer had them available so got an AV560 as replacement! The downside is that one of the uses I have it for is copying my photos across from my camera when I am out and about, but as the hard drive can lock up without warning this is not satisfactory. Don't get me wrong, ALL hard drives are prone to this, but the Archos seems especially flaky.
I was interested to read the post about most problems occurring whilst the player is being used whilst charging - I would concur with this. My wife's unit has been far more reliable than mine and she uses hers mostly on the train, whilst mine is usually plugged into my stereo (and hence left on charge a lot).
Despite treating my Archos extremely delicately I have had the following problems:
I have had the problem with the right half of the screen turning negative.
I also had a weird horizontal bar wipe effect happen today where the screen turned white and the unit needed to be repowered.
Also I find that when I select an album folder to play it often starts to play the first track but no sound comes out (the track is in fact not really playing despite the play icon showing) - if I skip to the next track it starts playing OK, and I can then skip back again. I've just upgraded to the latest firmware, so hopefully it will become a little more stable.
On my last unit, it also developed the problem where it would boot up only to shut off instantly (on battery power) or frieze on the boot screen if on mains power. Removing the battery doesn't help. From what I can gather this is a hard drive issue, and I have read elsewhere that it may be resolvable by removing then reseating the drive. THIS WOULD LIKELY INVALIDATE THE WARRANTY though, so I've never bothered to try it. Back to the shop it went!
Although Archos does seem to put out a reasonable number of firmware updates their tech support is a joke, I just go back to the retailer these days.
Finally, would it really have killed Archos to put a hard reset switch on these things???
When my current one dies I think I will ask the shop if I can use it to go part way towards a new laptop...