In order to effectively use the Archos devices, you can't really charge through USB. I mean, you sort of can, but it's so limited that it's not practical. This is because standard USB 2.0 is limited by current, and the device uses a LOT of power (and has a pretty sizeable battery to provide it).
If you can find a DVR station anyplace, you'll be glad you did... I personally own five of them (and have a total of four Archos devices... a Gen6 A5IMT (250GB), and FOUR Gen7 A5ITs (two at 500GB, one at 16GB, and one at 88GB).
The units are still terrific for ALMOST everything... except for internet (not for anything having to do with the devices themselves, but rather due to the built-in browser not being able to support the evolving internet-active-content standards, and thus not displaying many pages accurately, or "jamming up" or rebooting on especially content-heavy pages (just try to load a page with DISQUS comment sections, for example).
Your best bet for finding accessories compatible with this (including chargers, etc) is either to go to Gomadic (http://www.gomadic.com/
... they make modular cables and so forth and have an Archos-specific plug module which, combined with their high-output chargers, works perfectly) or to NewMP3Technologies (http://www.newmp3technology.com/archos- ... ories.html
I've bought from both, and have been happy with my purchases.