Attn Sports shooters!! Neep Help

Hi all,

My lovely wife gave me an awesome Valentines gift. I will be the team photographer for the NJ Nets basketball team for 1 game against the Chicago Bulls. I'm excited and nervous at the same time.

My question is, which lens do you guys recommend ? I'm willing to purchase 1 more lens for my arsenal. The game is indoors of course, the arena is pretty well lit.

My gear right now:

40D
50 1.8
10-22
18-55is
55-250is
50-500 Sigma
100macro 2.8
580 exII flash

Any suggestions will be great.

Thanks, Tony B.