Here are the specs for what we think you can currently get (as well as some history so you can track advances in technology, and computer processing value):
......................Processor.......Memory........Harddrive........Price
Aug 09...... 2.1 GHz(x2)......4 GB...............320 GB...........$500
Aug 08...... 1.9 GHz(x2)......3 GB...............250 GB...........$550
Dec 07........1.6 GHz(x2)......1.5GB.............120 GB...........$550
Various models will have different specs -- but if you shop around, you should be able to get these specs "on average" (and over time, improved specs at better prices!). We usually find the best prices at Best Buy, and sometimes Costco/club stores. Once in a while, Amazon has some good deals.
We prefer the big names such as HP/Compaq, Dell, Toshiba & Gateway. If you like the Sony name, you will pay slightly more. And of course, some people prefer the styling of the Apple Macbooks -- but that's a different category.