A few questions about my proposed system?

[headbanger2894]

I am a total newbie so I am open to any suggestions and all help is greatly appreciated.
Firstly, will there be any compatibility issues?
I'm shopping from Ireland so Ebay seems to be my best bet.
Also, I do realize that I don't have a case. What should I look for in a case? Any suggestions?
Anything my system is missing? I'm going to skim on the dvd drives for now, as I make absolutely no use out of them.
Is there anywhere I could shave off some $$$?
Also do you think that my motherboard bundle is an overkill? I want a system which I can handle graphics upgrades in the future without bottle necking.
Don't be too harsh on me if I have forgotten something vital!

Motherboard bundle:
http://www.ebay.ie/itm/Gigabyte-Z68AP-D3-Intel-i7-2600-3-4GHz-Quad-Core-CPU-16GB-RAM-Motherboard-Bundle-/360448175037?pt=UK_Motherboards_CPUs&hash=item53ec62abbd

GPU:
http://www.ebay.ie/itm/Palit-1GB-Nvidia-GeForce-GTX-560-Smart-Edition-GDDR5-PCI-Express-Graphics-Card-/200731601421?pt=UK_Computing_Computer_Components_Graphics_Video_TV_Cards_TW&hash=item2ebc892a0d

I am not willing to spend more on these particular items unless a slight price increase will lead to a substantial gain in power.

 

[azeem40]

For gaming, you are not getting a good deal. Both the MOBO&CPU bundle and GPU are overkill and underkill, respectively. Get an i5-2500k+Z68 Extreme3 Gen3 and a Radeon 6870.

i5-2500k: http://www.ebay.ie/itm/INTEL-Core-i5-2500K-3-3GHz-6-MB-L3-Cache-Socket-LGA-1155-OEM-/270962071136?pt=UK_Motherboards_CPUs&hash=item3f16991660

Z68 Extreme3 Gen3 ASRock MOBO: http://www.ebay.ie/itm/NEW-ASRock-Z68-Extreme3-Gen3-Motherboard-Free-Delivery-/270948965988?pt=Motherboards&hash=item3f15d11e64

GPU: http://www.ebay.ie/itm/XFX-Radeon-HD-6870-2GB-DDR5-Fantastic-Graphics-Card-/200749193987?pt=UK_Computing_Computer_Components_Graphics_Video_TV_Cards_TW&hash=item2ebd959b03

$100 cheaper than your choices.

For $100 more, you can get http://www.ebay.ie/itm/NEW-Asus-ATI-Radeon-7850-HD7850-2GB-DDR5-Video-Card-HD7850-DC2-2GD-5-/330714040627?pt=PCC_Video_TV_Cards&hash=item4d0017c933
It is MUCH faster than the GTX 560 or the Radeon 6870.