Which ever book you choose, as all books are good in its own respect, believe in it and you will succeed. As already said- RTPs are very important.
In search of the best reference books I've just compiled this info from various suggestions in this club.
BOOKS FOR CA FINAL:- In order of most recommended.
Paper 8: Indirect Tax Laws-
1)Yogendra Bangar, Vandana Bangar *- 580/-
+ Compiler Rs 350/-
2) Ajay Jain- 700/-
3) K. Vaitheeswaran- 425/-
4) Padhuka- G Sekar, B saravana prasath & Saimukundhan, 453/-
5) Govindan 450/-
6) V. S Datey Rs 495/-
All the best