AMA: Padhuka. ISCA : Dinesh madan or padhuka( here don't go with Manish valecha, because content is not enough for the exam). DT: Vinod Gupta, if u have a lot of time OR if u r attempting in may15 then go with G.Shekar padhuka, it has two books. Presentation for self study is very gud. IDT: If u dint like bangar & bangar then go with padhuka. This time padhuka for IDT is very gud. Along with this all practice manuals latest edition especially for dt and IDT. For AMA & isca, last year edition is enough.
In AMA padhuka, u get many rtp questions so u need not worry about for how can I collect old rtp's. For DT and Idt, also buy institute's supplementary material and case laws book. This two books are essential for ca final students.