I'm trying to avoid wasting money+time on this if somebody already did this. I would need to go buy motherboard, install it in PC case, test it with LinuxMCE (lots of lost time if it fails).
Then if it fails and can't be easily supported by LinuxMCE I need to sell that motherboard and try again... that is what you are suggesting, right?
Well I would much more to listen to other peoples experience and get the motherboard that works the first time.
Ok, I will repeat myself! And add a little further info from other posts of mine on the subject to try and clarify.
Most importantly: You cannot
ask a question like, is there any ATX board that works, and expect to get a meaningful answer.
There are literally thousands that would work, how can you expect forum members to recommend one to you from such a broad criteria? What criteria would they use to suggest one particular board over another? The question is far too broad. Tip: when posting a question on forums, narrow the focus of your question as much as you possibly can. Make it easy for others to answer your question, otherwise you won't get any answers at all (or silly/inappropriate ones!)
Secondly: You can narrow that focus by specifying exactly what you are looking for beyond "ATX". eg HDMI and SPDIF outputs, nVidia chipset, at least 3 PCI + 1 PCIe slot, AMD64 socket, 4 SATA connectors, 6+ USB connectors, etc, etc. And then hope that someone out there happens to have something that matches this.
However - it is very often the case that either your particular specification might not match with those people who happen to read your post. And even if they do, commonly, a board that has been around long enough for people to have a good feel for it working are already discontinued due to the short life span of many boards!
This is why I am trying to recommend to you that you shouldn't focus on a particular board ... increase the chances of success by looking at the question "smarter".
It isn't mobos that are compatible with Linux or LMCE, it is individual components on the mobo, and these usually have much longer life spans. I have already mentioned the critical areas. Find some mobos that 1) is ATX, and 2) meets your requirements for the other options you are looking at (ie PCI slots, video/audio connectors, USB ports, etc). Now eliminate any that don't have nVidia GPUs (best case, and something in the 6200-7300 is ideal for most purposes).
You now have your base. Now list what audio and NIC chip they have. Check on the boards/wiki for those chip numbers - if they are common then you will find someone confirming they work. But at a minimum, check with the manufacturer's web site for a Linux driver (that works with kernel 2.6.22-14). You now have networking and sound. Often it is worth checking with the mobo manufacturer's web site for the overall Linux compatibility.
There are very occasionally issues with SATA. But by in large, get an nVidia chipset, and confirm that the sound and NIC chips have drivers for 2.6.22-14, and you're done! This will give you many more mobos to choose from than hoping that someone out there happens to have a mobo like what you are looking for, can confirm that it works, and is still available!