upgrade helps

What upgrade would you rec for me i like to watch alot of movies and i save alot
of video AND I MEAN ALOT and i extremly fast computer.

here my specs of my computer

Windows: Windows XP5.1 (Build 2600) Service Pack 2
Internet Explorer: 6.0.2900.2180
Memory (RAM): 511 MB
CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz
CPU Speed: 2990.9 MHz
Sound card: C-Media Wave Device
Display Adapters: NVIDIA GeForce FX 5200 | NetMeeting driver | RDPDD Chained DD
Screen Resolution: 1024 X 768 - 16 bit
:
Network Adapters: ADMtek ADM8511 USB To Fast Ethernet Converter - Packet Scheduler Miniport | Realtek RTL8139 Family PCI Fast Ethernet NIC - Packet Scheduler Miniport
CD / DVD Drives: D: TEAC DW-552G
:
COM Ports: COM1
LPT Ports: LPT1
Mouse: 5 Button Wheel Mouse Present
Hard Disks: C: 74.5GB
Hard Disks - Free: C: 7.8GB
USB Controllers: 5 host controllers.
Firewire (1394): Not Detected
:
Manufacturer: American Megatrends Inc.
Product Make: P4IPE
:
AC Power Status: OnLine
BIOS Info: ATAT COMPATIBLE 091004 A M I 9000410
Time Zone: Eastern Standard Time
Battery: No Battery
Motherboard: soyocomputer P4IPE
Modem: Not detected

with video, it is especially important to have a high end graphics card and lots of ram. Double your ram to 1gb.

If you like movies, get a humungous hard drive - 1tb or more to store. Movies eat hard drive space like candy.

any thing alse i should upgrade