Spurs vs Suns, Spurs vs Lakers, Spurs vs Mavs were all great rivalries during the '00s. All of those games whether it was regular season or playoffs was must see TV. The biggest problem like you said is these stars hop around trying to form super teams or create teams that tilt the advantage in their favor ala Lebron going to the Lakers and getting Davis. You had guys like Duncan,Dirk,Kobe,Miller,Malone,Ewing,Hakeem, either stay with the team their whole entire career or for most of their career. You don't have that anymore and it greatly hurts compe ion and stops rivalries from forming. We don't have any great rivalries right now in the NBA. Maybe Nuggets-Clippers, Clippers-Mavs might turn into something the next few years but we'll see.