new pc or get new ram?

[NightLinks]

I have been thinking about getting me a new computer case to replace the one that i currently have. I have a apevia x-superalien full tower and i want to replace it with a cooler master centurion 5 blue mid tower so that it can fit in the shelf on my desk. I know that if i get the new computer case i'm going to feel like building a new system. What i am thinking now is to get 2 new sticks of 2x 2gb of ram to replace the 2x 1gb sticks that i have now. I have 2x 1gb extra ram that i am not using because my system gets unstable when using all 4x 1gb sticks of ram in all 4 slots.

My System:
Case: APEVIA (ASPIRE) X-Superalien
Power Supply: OCZ GameXStream 600W
Processor: Intel Core 2 Duo E6600
Motherboard: ASUS P5N32-SLI SE Deluxe
Video Card: EVGA GeForce 8800GTS 320MB
Memory: Patriot EP 2GB DDR2 800 (PC2 6400)
Hard Drives: (2) Seagate Barracuda 250 GB 7200 RPM 8MB
DvD Burner: NEC DVD-Ram 18X
Floppy Drive: ALPS 1.44MB 3.5"
OS: Windows Vista Home Premium 64bit

[Hazz]

I wouldn't bother upgrading at the moment, your system is still a very powerful machine.

I would upgrade the RAM for now as you can pick up 2Gb ddr2 for around £30 here in the UK.