I am still using a 775 CPU, the new 2011 generation is very nice, i am planning to buy a lap top and it would be with some of those CPUs, Their performance is very nice, even if it is an I3 Cpu.
i3 on a laptop? That's really not a performer, no idea where you got that impression from. That's just low end. If you want the battery to last long then I'd recommend U series. If you want to also have decent performance then go for the newest i7 - U and you should be good. I have that on my laptop and it's perfect (for my current needs).