Out if EB Games, JB Hi-Fi, GameTraders and GAME, GAME offer the best trade in value. Just remember you may have bought the game for $90-$100 a few months earlier but if they're currently on sale, not selling well or a few years old, then you won't get much for them. I've seen a few of your games listed at low prices ($20-$30), which is probably why you didn't get much for them.
Probably best to check eBay beforehand to see if any are selling at a higher price or trade in elsewhere. I've rang up places before and asked what the trade-in value is before i took them in. Just remember console games don't hold value like Transformer toys do.