Well to be honest, I do deal with large amounts of data, but It would just be the work stuff on the drive, I think the 120gb is a good size with the 1tb drive for backup.
What the drive would have on it is:
Windows 7
ArcGIS
SPSS
Football Manager 2013
and I suppose to get the best out of the drive I would need to put the files which those programs use (data & savefiles etc) on the drive as well?
I am struggling with the graphics card as I can see know way of comparing them, the processors, memory and hard drive all have a numerical element in the name (120gb/ i7/ 8gb) but I have no idea how to compare graphics cards and how to see what they are capable of doing. For example, I have no idea what the difference between:
MSI HD 7750 2048MB GDDR3 PCI-Express Graphics Card -£74.99
and
MSI GeForce GTX 650Ti OC Boost Black Knight 2048MB GDDR5 PCI-Express Graphics Card - £134.99
By the way, thank you everyone for all this help, the response has been remarkable

. Especially seeing as I have only just joined!