Salut Hugo.
Although it does not really match your specifications, you may be interested by my last laptop purchase experience. I was looking for a lightweight laptop, 10 inches, without paying for a Windows license I would not use, and with good Debian testing support too.
There was not much choice here: the only netbook manufacturer to offer a rather easy Windows tax refund is Asus. The graphic chipset embedded in the current Intel Atom processors require a lame proprietary driver and suck with free drivers. Asus and Acer, the last netbook manufacturers, are going to eventually abandon that market.
With all that context, there was almost only one model left: Asus Eee PC 1015BX. Cheap, using perfectly supported AMD graphic chipset and wifi card, without requiring any proprietary firmware. Asus has agreed to refund me the Windows tax, I am now waiting for their transfer.
That laptop is not perfect though, and I have discovered three significant problems with it: * it has an EFI firmware, which is fine for configuring the motherboard, but almost unusable to boot because it implements an old version of the UEFI specification (so I am booting that laptop in BIOS mode, which works fine); * they only put a single loudspeaker, the right one I think, so the left channel produces no sound; * they only put a single hybrid microphone/headset jack, which may or may not work with telephone-type four-rings jacks for mic/headset combos, but I have not tested that yet.
Hope it helps. If you decide to buy a netbook, hurry up, because the last ones are currently being sold in discount, and there will probably be not new ones after that.
Librement,