I looking to buy a new laptop to replace my existing Fujitsu siemens amilo, here are requirements:
1). Ability to carry in my bag or in my hands, so 13" or even smaller ones like netbooks are attractive.
2). Ability to use on bus, train or any journey and during other travel requirements, so long battery life.
3). Quiet use and low heat dissipatio:, my amilo is very noisy and very hot.
4). Highest possible ram(2GB++), Good hardisk(80GB+), Good processing speed so that it can work most applications in next 3-4 years.
5). Robust build : I hate the manufacturer when my machine breaks down. My amilo is good in that aspect, because it has good build and is in working excellent condition despite heavey use for my PhD.
6). Low cost.
7). Usage : Wordprocessing, Presentations, Youtube, Web browsing, Movies, dedicated game card is not required although built graphics capability should be as high as possible.

Here is my compilation of models that might be suitable:
Dell
13" vostro model looks excellent in specs, and cost only 349£.
http://www1.euro.dell.com/content/products/features.aspx/iip_notebooks?c=uk&cs=ukbsdt1&l=en&s=bsd&dgc=BA&cid=5186&lid=121454