This nice Wiki Page describes how to make your plain and simple EeePC into a super fancy notebook by doing some internal upgrades. Soldering experience required!
(Because of the extensibility of the article and EeePC, I will just put some of the upgrades here.)

USB hub

GPS with antenna

Bluetooth

FM transmitter
Power switch
Card reader

Popularity: 16% [?]

Popularity: 16% [?]

 informationweek.com writes:
Until recently, Linux PCs were about as easy to find in stores as a vinyl record. Now, personal computers with the Linux operating system pre-installed are becoming more readily available, thanks to new models from upstarts and established PC makers — and disappointment withMicrosoft (NSDQ: MSFT)’s new Windows Vista OS.
In just [...]

Popularity: 16% [?]

It is not surprising why the Eee PC has taken off so far since its release. People want to see something new and innovative without breaking the bank. And that is what ASUS has given the geeks and non-geeks alike around the world. Eee PC is a truly innovative piece of technology that is affordable [...]

Popularity: 17% [?]

For those who are going ga-ga over the newest technology craze released by Asus, the EeePC, this news is a big one. In the EeePC Blog, a customized OS for the EeePC was made available based on Xubuntu. Ubuntu is known to run in EeePC but there are some settings needs a little tweaking [...]

Popularity: 12% [?]