Need Help On a Spec For PC

Hey Everyone,

I've never built a PC before but my current one is getting old, so decided i'm going build one as i hate all the junk that comes on most new PC's

Anyway i need help please

I use the computer daily, run multiple Softwares that do alot reading and writing of mostly txt files
always have multiple softwares open too like photoshop, programming IDE, browsers and other programming softwares etc...

Dont need monitors have these but needs to support dual monitors

Harddrive dont need to be huge as most files for work are stored on a external hard drive

Just really need help and advice with out it i just know i'll end up with parts that hate each other

Oh and i kinda like this case http://www.amazon.co.uk/Zalman-Z11-Performance-Desktop-...
just incase you need to know



Any help or spec would be appriecated


Thanks