2.0 / 1.6 = 1,25 or something that takes 2 hours to compute at 2GHz should finish in 2.5 hours on the 1.6GHz machine. Since you can never change the CPU (some may disagree) it's a good idea to get as fast a CPU as you can within reason. For example if the bump from 1.6 to 2.0 is 100 bucks, well done. If the bump to 2.2 is 500 bucks I would pass.
Take a moment and consider reading http://news.cnet.com/8301-17938_105-10064769-1.html which has a fairly current list ranked by price.
I have not found such a site that can keep up with the flood of models.
I just started shopping for a new laptop. There are so many brands with so many different features, it's difficult to separate what's important from what's not in computer specifications.
(1) First, what in practical terms is the difference between an Intel Core 2 Duo 1.60 Ghz chip and the same chip running at 2.00 Ghz? Where will the difference be felt and is it really noticeable?
(2) Is there a buyer's guide web site that can help narrow down the choices to be made in purchasing a new laptop? For example, a web site that asks you questions about what's important to you (use, cost, weight, size, etc.) and then presents the laptop choices from the web site's database similar to what you need? Any other web sites or ways one can winnow the many laptop choices when going shopping?