Start with some motherboard where you have space for all cards needed and you are fully supported. Not all motherboards are guaranteed to work but most are good.
If you want some kind of fully supported laptop look further down the page.

Intel Q6600 Quad, Nvidia GF6200, Soundblaster-Live CT4760, Atheros wifi card 
For the cards you want you would need 1 pci slot (sound card). 1 pci mini-express port (wifi card) and 1 pci-express port (gfx card).

AROS SMP is in the works but in beta status. Click here for demo of this computer rendering using all 4 cores. 


Core2Duo 1.6G
Hz 15" 1024x768
Need wi-fi replaced card. Easy to charge from under the laptop with this one.- Atheros AR5BXB63
Can be found very cheap on e-bay.

Celeron 1.6GHz 15" 1280x800
Fully supported

ACER Aspire One
Atom N270 1.6 GHz - 8.9" TFT 1024x600

Fully supported models are ACER Aspire One A110, A150 and ZG5.  

Hardware to run AspireOS.

This is the kind of USB wireless network card you would need if your network hardware is not supported by AspireOS.
It can be found on e-bay Click Here.

It is also possible to use USB Eternet card based on dm9601 chip.

Click link under for more hardware AROS supports: