As long as it has a VIA VT8500 or WonderMedia WM8505, it should be all right.
Do not get the ones with AKARM/Anyka processor as it is another system on chip (SoC) which has no public Linux port / not supported by Linux. Systems with Samsung ARM SoCs should have a Linux port as well but tend to cost slightly more.
The Linux port for the VT8500 has no sound and wireless probably is not working, but apart from that, works very well (albeit with 2.6.10, which is a bit outdated). This is what I use on my netbook. There are sources on the internet, even if many drivers are only in object code format because they were not open sourced by VIA
The port for the WM8505 is based around a 2.6.29 Android kernel, and has no public sources released for it, but it can run Debian well and from what I know also supports sound (I only have a VT8500, so I can't test it first hand) - wireless seems to work as well.
Many will be WonderMedia WM8505 nowadays and less VIA VT8500 (it predates the WM8505, in fact)
Just look out for AKARM or Anyka. If you see that don't buy if you want Linux (and you don't want to port it).