Ann: Quarterly Report December 2015, page-11

Always depends on your risk profile Esh.
CVN lowest risk without a doubt.
AWE - just did a asset sale and will be net cash for the first time in a long time. Very secure long term gas sales...
BRU. Enough cash for another 12-18 months with some onshore drilling and uncon potential, perhaps biggest upside, but... could fall perhaps another 20% if their drilling campaign is unsuccessful.

Copper - AVB, safe but IMHO, not cheap.
TGS - amazing cost of production, but.. high debt.

Hope that gives you a starting point