Doubting between i5 750 and AMD x4 945 build

Hello there,

Im going to give my old rig a decent upgrade and got my doubts between AMD and Intel. The components that Im going to upgrade are:
- Motherboard
- Memory
- Graphiccard
- CPU

Im doubting between these two:

(1)
AMD Phenom II X4 945
Gigabyte GA-770TA-UD3
EVGA GeForce GTX 460 SuperClocked 768MB
4GB DDR3 GeIL memory (GV34GB1333C9DC)

Total costs: 490 Euro's ( 630 US Dollars)

(2)
Intel i5 750
MSI P55-GD65
EVGA GeForce GTX 460 SuperClocked 768MB
4GB DDR3 GeIL memory (GV34GB1333C9DC)

Total costs: 570 Euro's (733 US Dollars)

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Im building this setup mainly for gaming. I dont photoshop, make movies or whatever.. Just gaming, internetting and downloading. I also am NOT overclock my system.
Since im from The Netherlands I cant use any tips about ordering some special sale at Newegg or some other shop outside my country. So just use the information im giving  .
Originally my budget is 650 $, but I might up it for the i5 if its really worth it.


The questions I got are:
1/ Is the i5 setup worth the extra 100 $ ? If yes, why?

2/ is it necessary to change the stock CPU cooler or are both CPU's doing fine with the stock one? (for example: If the i5 rly needs a different cooler, then the differents between the price is even higher than it is now.. )

3/ If I go for upgrade (1) is the ''Gigabyte GA-770TA-UD3'' the right way to go? Or will the ''MSI 770-G45'' be just fine? Which is around 25$ cheaper.




Greetings,
Tom