What should I Upgrade?

I currently have:

PowerMac G5 Single 1.8ghz(late 2004)
1.25gb RAM(PC3200)
80gb HD(7200RPM)
300gb HD(7200RPM)
X800XT 256mb graphics card
8x SuperDrive
Bluetooth
AirPort Extreme
250gb HD(external)

I have some money to splurge and I was just wondering what the best way to spend my money would be? RAM? Raptor? Anything?

I do video editing with After Effects and find it a little slow, same with Photoshop CS3 beta and iMovie.