Intel core i series processors vs 2 duo core processors

really depends what you do
if you are just a internet browser,email,IM and Facebook Farmer
then you dont need the I5
if you do encoding,video editing,heavy gaming with latest games
then go for better system

I mean the decision to spend your money is up to you

Do you need a Honda Civic or a Ford Mustang GT?
I love car analogies.....

it depends on the exact type of i5. the new i5 2500k is very good compared to a high end core 2 quad http://www.anandtech.com/bench/Product/48?vs=288 the lower end older i5's arent much of an update http://www.anandtech.com/bench/Product/48?vs=109
compared to a core 2 duo there isnt much competition http://www.anandtech.com/bench/Product/54?vs=109 but it really depends on the exact processor you currently have. core 2 duos can be overclocked very easily also. a 3ghz core 2 duo can still play any game with good fps.

Um, we are talking about laptops, crowe... Not a very good idea to overclock a laptop o.O

Are these the models ? : http://www.anandtech.com/bench/Product/241?vs=343

If they are,well, this is strange ... the 2010 with c2d is getting better fps in games.

Are you sure you want to buy a laptop and especially an Apple ? If you dont travel, you dont need a laptop. For the price of an Apple laptop you can build yourself an awesome work\gaming rig.

It sounds to me like you want to stay with up to date components so the i5 would be good. If you are only going to be online and watch movies you do not need an Intel core i5. If you are going to be using it for videos editing and encoding, the i5 will be the best choice. I personally would want to go with the i5. So in conclusion web and movies get the core 2 duo. Video editing and encoding the i5 would be the best option.