How to buy laptop without bottleneck.

Hi,
I am looking for a new laptop and I want maximum value for my money, so can anyone please advice on how to buy a laptop with the least bottleneck possible?

For example, if I get i3-330M processor, what is the minimum I have to get for my RAM in order to not to get a bottleneck. Is it enough to get 2x1GB-DDR3 PC 8500? Must I get something with a faster like DDR3 PC 10600 or bigger like 2x2GB?

Also, to get the most value for money, what is the sweet spot for i3 processors? Is it the 330M, 350M or the 370M?

Thank you all for your kind attention and quick reply.