Yep, the card you have would be good for watching HD movies/Blu Ray. Although the 8600 is better for gaming, your card will work great for watching HD stuff.
mATX rig: TT Lanbox Lite, GA-G33M-DS2R, q9300, 4GB G.Skill Pi PC8000, 2x640GB Samsung F1's in RAID 0, LG 20x DVD+/RW, HIS IceQ HD4670 512MB, Gigabyte G-Power PRO, TT 450W TR2 RX Modular PSU
HTPC: i-Cute iBox, GA-MA780GM-S2H, 4850e, 2GB G.Skill PC6400, 1x640GB WD SE16, Onboard HD3200, D-link XtremeN PCIe, Leadtek WinFast DVR3100 H Tuner, 450W Vantec PSU
Server: Custom made case, EPIA Mini-ITX mobo, 1GHz VIA, 1GB PC2700 SO-DIMM, 1TB WD, Gigabit PCI LAN card, 60W 12V AC adapter