The pink-flowered Gymnocalycium is really nice. I've seen similar Gymnos before but they seem usually to be red or white flowered.
I particularly love the caput-medusae... I think it would probably be the most striking of all cacti that I have seen. It's just so
unusual. If anyone in Australia knows of where I can get one (grafted specimens prefered), please let me know! Also, could you tell me what the Echinopsis is in the bottom left corner of the last photo? I have a very similar plant but I am unsure of its ID.