Well dear... the choice of books depends upon how much you already know.. .. i mean how much you have learned in last two years.. in physics...go for NECET and HC Verma, if you have problems with basic concepts... you must be able to solve HCV all by yourself.. and dont neglect additonal questions in NCERT.. and then if you have time... go for arihant... in chem... read NCERT once or twice... and after that move for any good book... and use Morrison and JD Lee,but only as referece books.. cause they may waste ur time... in maths... arihant set is nice to solve... i ve suggested the books i like... you can go for any set of books u r comfortable with.. what is important is that you solve one book completey before moving to another... dont read a little from every book in the market..
better aim for top 50 if you want cs.. or at least top 100.. if dual degree will do...