Graphical Calculator for AS/A2 Maths and Further Maths?

I am expected to buy a graphical calculator for my AS/A2 maths and further maths but I do not know which one to choose. The modules I will be taking are; C1, C2, C3, C4, FP1, FP2, M1, M2, M3, M4, D1 and D2. Any suggestions?