I am planning to buy a new notebook. Mine is going to be 3 years old by January 2010.
There are several reasons why I want to get a new notebook:

1. My 160GB hard disk is filling up. Nowadays, I have to periodically archive some older stuff to an external hard disk
2. I am doing more post-processing on photography and my T5500 with Integrated Graphics is chip is slow.
3. Windows 7 is shipping soon (see below news). I installed Windows XP on my Inspiron 640m. Windows 7 is getting a lot of good reviews and I am excited to move to a new OS.

Windows 7 and Server 2008 R2 will be ready by holiday 2009 – Ars Technica

At Microsoft TechEd North America 2009, Microsoft today announced that Windows 7 and Windows Server 2008 R2 will both be available to customers in time for the holiday shopping season