5Ds has those "Earthbound Immortals" as the antagonists, right? I actually have one of the cards--the hummingbird (they all have difficult-to-pronounce names). Quite the ridiculous card effect. 5Ds also introduced Synchro monsters, which, IMO, left Fusions and Rituals in the dirt. But I guess it's an improvement.
The last Yu-Gi-Oh! game I bought was Championship 2008 for the DS, so I assume the newer ones are much better.
My favorite deck used the batteries cards. Swarm on the offensive and play Short Circuit. Heheh, good times.