Get him a cheap POS and keep the extra $$$$. Lol
That tv is probably gonna have some serious lagggg.
Get this
AMD X2 4400+
DFI Lanparty SLI
7800GTX 512
2GB G.skill extreme or OCZ
nice big Sata II Hard drive (Western Digital or Seagate)
PC P&C PSU
Good looking big case (up to you really)