Is your rig ever really "done?"

Have you ever considered your rig to be complete? Have you ever found yourself satisfied with every component in your system and not felt the to constantly change or modify your setup? When are you ever really done?

I just completed my first system a few weeks ago, and I find myself at a crossroad. I'm just getting my feet wet when it comes to system building. Everything works fine in the system, but I find I cannot stop thinking about starting over.

This is my current setup:

CPU: AMD FX-8120, stock settings and stock CPU fan
Board: MSI 890 GXM AM3
RAM: 16GB G.Skill @ 1333
PSU: Coolmax 750Watt ZP series, modular
GPU: Radeon HD6650
Case: Antec 300
Windows 7 Home
Corsair Force GT 120 GB SSD boot drive
WD 1TB Caviar Black HDD for storage

Everything is fine with this system. Fires up like a champ. This damn thing is barely three weeks old and I feel like I want to build a whole new system already! I went slightly over my initial budget because I felt the need to go SSD/HDD combo. The GPU isn't that great, but it plays Diablo 3 so I'm fine. It's a micro ATX board, but to be honest I see no problem with it, really. I think every other part on that list is pretty decent.

However, I'm a heartbeat away from ordering a new case and new mobo just because those two parts I have in mind look nicer to me. White NZXT Switch 810 because it's bad ass, and an all black mobo, perhaps the Asrock 970 or Gigabyte 990 FXA UD3.

It makes no sense to me, so I cannot hope to explain to a rational person why I spent so much money, time and energy into a build only to scrap it and start over just for looks.