Hi all, am new here so please be gentle 
Hope you guys can help me out
I have a PC that I built a few years ago, it mainly comprises of:
Asus A7n8X Deluxe Motherboard
AMD Athlon XP 2400
256MB ram
Ati Radeon 9000 pro 128MB AGP graphics card
Maxtor 80GB 8MB Hard Disk
Pioneer DVD RW
I don't know whether to upgrade it, perhaps to 2GB ram, maybe an additional ATA hard disk and a 19" TFT, and perhaps a new sempron processor (?)
or,
to build a new system and keep this one as a spare. (New sys: Core 2 Duo E6300, 1GB Ram, ATA HD, nVidea Asus Extreme 7600GS Silent 512MB DDR2, Asus P5B Deluxe or Asus P5WDH Deluxe motherboard).
I really don't know what to do :-/ Should I just upgrade this system and make do for another six months or so? Or spend double-ish and build a new system? Will there really be that much difference in performance between the two?
I will be using it mainly for photoshop, along with web browsing etc plus some video editing. (I don't play any games on the PC so am not too bothered by a high spec 3D card - I just need it for photoshop and video editing really)
What do you guys think? Hang on a few months? Maybe just upgrade my current system to hold up for another 6 to 8 months perhaps? Or just go ahead and build a new system?
Thanks in advance for any help!

Hope you guys can help me out

I have a PC that I built a few years ago, it mainly comprises of:
Asus A7n8X Deluxe Motherboard
AMD Athlon XP 2400
256MB ram
Ati Radeon 9000 pro 128MB AGP graphics card
Maxtor 80GB 8MB Hard Disk
Pioneer DVD RW
I don't know whether to upgrade it, perhaps to 2GB ram, maybe an additional ATA hard disk and a 19" TFT, and perhaps a new sempron processor (?)
or,
to build a new system and keep this one as a spare. (New sys: Core 2 Duo E6300, 1GB Ram, ATA HD, nVidea Asus Extreme 7600GS Silent 512MB DDR2, Asus P5B Deluxe or Asus P5WDH Deluxe motherboard).
I really don't know what to do :-/ Should I just upgrade this system and make do for another six months or so? Or spend double-ish and build a new system? Will there really be that much difference in performance between the two?
I will be using it mainly for photoshop, along with web browsing etc plus some video editing. (I don't play any games on the PC so am not too bothered by a high spec 3D card - I just need it for photoshop and video editing really)
What do you guys think? Hang on a few months? Maybe just upgrade my current system to hold up for another 6 to 8 months perhaps? Or just go ahead and build a new system?
Thanks in advance for any help!