Help explain laptop specs for me? £350

[davestar_delux]

Hi, I am looking for a new laptop and not sure what specs or features I should be looking out for? I am reading as much as I can on this forum but don't understand a lot of the terminology now, it used to be just pick the most MHz and most GBs, what are i3 and i5 and i7 and how do these compare to multiple cores etc?

Also, what are good graphics cards? And is a seperate one necessary if not playing games? Does it help films?

 

[davestar_delux]

Games aren't a big issue - I don't play any although might try out a few retro ones. I like the odd film and would like to output to a TV when at parents or friends only but not a massive issue. It will mainly be used for programming/development though.

I figured about the 15' screen, what is a good resolution likely to be?