Upgrading my PC

[Sentrosi]

Current PC

1. Motherboard: EP35C-DS3R
2. Processor: Q9550
3. RAM: 8GB DDR3 1333
4. Video Card: Gigabyte 6950
5. Hard Drives: 3 500GB SATA II Drives
6. Monitor: Westinghouse 22" 1680x1050
7. Power Supply: Coolermaster Silent Pro 700W

So that's my current PC. I currently have an old Asus 4850 video card and an e8400 processor. I'll probably sell those for around $175-$200 on my local Craigslist. I was thinking of doing a CPU/Mobo swap and get an i5 3570k and a Z77. I would sell my existing Gigabyte/Processor combo for around $350-$400 probably on CL as well.

I could probably go out and get those upgrades, but then I look at my lonely 22" monitor. The monitor is still going well, but I see that the Planar 27" monitor I've had my eye on is around $250.

So now is the issue at hand.

Should I go with my gut, sell my old Video Card/CPU combo for $150-$200 and get the monitor?

OR

Should I wait a bit, sell the four items as a combo deal for around $450?

OR

Do something differently?