enough HP for r9 280x

[knows_something]

Hello i have to choose a new psu for my computer.

I have:

 

-intel core 2 quad q8300 @2,5GHz

-mobo: gigabyte ga-ep45-ud3l

-Kingston DDR2 2x2GB

-9800GT 1GB/ (R9 280x OC by Power Color)

-Chieftec 550w aps 550s<-- current

 

I know my current won't support it (i have yet to install the 280x) and i need a replacment. It has come to my attention that it doesn't count just the Watts for psu but there are more stuff to it. So i've narrowed it down to 5 psus:

1. Cooler master B600 600W atx23- 51€

2. EVGA 600b- 59€

3. corsair VS650 650W- 63€

4. cooler master B700 700W atx23- 65€

5. Chieftec A-80 series 750W atx modular- 70€

I'm not sure if everyone fits and i really don't know what si the difference between 1st and 5th.

I intend to use it in my next build (probably this summer) so it would be great to be a rellyable one. I hope that you guys can help.