OT: Hardware recommendation for graphics card?

[Peter Alcibiades]

Friend of mine asked for advice on what sort of graphics card to put in a 
machine he is putting together for his kid.  It will be i5 probably, and he 
wants to get something that will be respectable with photoshop processing.  
An i3 of mine with onboard graphics was definitely not fast enough for him.

Is i5 even enough, should he go for i7?  Its not my area of expertise.  I 
am not even sure about the relative contributions of the graphics card and 
the processor in this.

Any suggestions gratefully received.  Money is an issue, but he wants 
something that will do a decent job first and foremost.

Peter