Hi Aimzz,
Based on your assumptions of your system I would like to tell you that you have selected the right power for your needs!
Don't forget like most, that if you are planning on keeping your computer parts for a long time, it might be worth noting that they all need power! So best checking out what rating the power supply will be. These days most well branded Power Supply Units feature bronze, silver and gold certification. Meaning that the quality of the parts over will will degrade less (depending on which certification you have gone for.
I would recommend you have a look around at the types of power supplies on the market before purchasing. Remember though, Its always best to have more than you need so that you do not stress any of the components, and always buy a good power supply that might even last several rebuilds. For the price difference Its worth getting the best you can afford at the right power rating. You never know when you might want to upgrade your graphics card and then all of a sudden realise that you need that extra 50w worth of power on your system!
Happy Gaming! and good luck with your purchase. Regards, [TCL]Dellstorm