Really depends on what you're looking to do. If you want incredibly long lasting and you don't care how slow it might be, then get an Atom processor as I think the max used is about 5-7. Other wise, Pentium Dual Core is about the sweet spot for general use laptops. Then there is Core 2 Duo, then Core 2 Quad, then the I7. There is also the Celeron Dual Core which comes before the Pentium Dual Core.