On board means built in to the processor or motherboard, they're not as powerful as a stand alone graphics.
The cpu/ram depends on what you're going to do with it, whether it's cpu intensive or ram intensive. Personally I'd go for ram, got 16Gb in my laptop and I still run out, but that's down to my workload being very heavy on ram. But ram is very cheap and can be upgraded easily (unlike the cpu), think my 16Gb cost about £80 about 6 months ago.
Thanks for clearing that up. What do you think about the two ones I posted links to? Value for money for what I'm looking for?