Here's another vote for Windows Server 2012 Essentials. I don't like everything about it, but having ruled out Windows 8 (no real server functionality) and Linux (I don't otherwise use Linux, so I don't know the quirks), that leaves WS2012E and WHS2011.
Of those two it mainly comes down to deciding which is worse.😛 WHS2011 has some very big drawbacks that turn me away from it. The lack of Drive Extender functionality is self-explanatory, meanwhile the inability to backup GPT disks is going to make WHS2011 near-worthless for backing up OEM Win8 machines since OEM machines will finally be shipping UEFI/GPT. WHS2011 is otherwise fine (shares, media streaming, etc), but since my primary uses are for file storage and client backups, WHS2011 falls flat exactly where I need it. Meanwhile both of those issues are resolved by WS2012E, which gives it a major leg up in my book.
Which is not to say that WS2012E is perfect, but the remaining issues can be dealt with. The Domain issue is no longer an issue thanks to the registry workaround, so for home usage you can for all intents and purposes ignore Domains. You lose VPN and Group Policy functionality, but I for one didn't want that in the first place.
Its only other notable quirks right now are related to Storage Spaces. Despite MS's claims otherwise, Storage Spaces is always operating in some kind of RAID-like mode; either RAID-0 (stripe), RAID-1 (mirror), or RAID-5 (parity). The point being that unlike DEv1, a non-protected pool is going to be striped over multiple disks, increasing your exposure to failure. In case you really don't mind losing a file, you're going to want every pool running some kind of protection (hooray parity). The other quirk is that it can't auto-balance disk usage (such as adding a new disk), which is incredibly stupid. Thankfully the workaround for that - creating a new pool inside the existing space and moving your data to that - is easy enough. All of these are quirks I can easily handle.
The real kick in the teeth right now is the price. If it was up to me, there would be a WHS2012 with the Domain/VPN functionality stripped out, the client limit dropped to 10, with Microsoft calling that a day. But it looks like MS doesn't want to have to deal with having such a low-volume version of Windows, so that's that. All I can really do is eat the cost for now, and plan on amortizing the cost of WS2012E over the life of the OS. Since it's a server product it gets 10 years of support, so if I can go for at least several years without replacing it then I can justify the cost. This is where being so modern is a big help, since at this point I have no reason to expect WS2012E to become outdated in only a few years, unlike WHS2011.
When it comes right down to it, WS2012E is the first Windows server OS that is a proper follow-up to WHSv1. It's going to be the best choice for covering WHSv1's major use cases while also being the easiest thing for a WHSv1 owner to adapt to. If you can eat the high OS cost it will be the best replacement for WHSv1.