1983 side was all abt fun. the mavericks, the underdog just kept on winning and winning until they lifted the cup
1985 side was probably better, almost an invincible look to it
2003 easily the top side barring Australia, who were the only ones to beat it
2008 Dhoni's young guns, along with Tendulkar
Having watched the highlights [even though they only show the good parts] of the '83 side and the '85 side, I can say the the 1985 side is probably the best ever India side, even though there is nothing like winning the WC and any side that does that is taken as the best .... the 1985 side had Gavaskar as captain, had some nice spinners and all-rounders, Srikant was doing Jayasuriya at that time, Shastri got the champion of champions award, Kapil was smashing runs, the catching was brilliant
I am going go for the 1985 side coz of the invincible look it had