Windows 8 Convertible Devices: What is the Perfect Size?

I think many will agree when I say how excited I am about having one device which functions as both a laptop and tablet, running Windows 8 (not WinRT). Finally, one device for every situation, no need to decide which device to bring where, and no more concerns about syncing files. Everything on one drive (and backed up somewhere else, of course).

My biggest concern when considering which convertible/laplet/tabtop to purchase is:

What is the ideal size to fit both needs?

Options:

10-11 inches: The Microsoft Surface may be the best looking device yet. This size is great for general internet consumption or playing tablet games, but in my opinion, I can’t imagine using such a tiny screen when trying to do actual work (Word, Excel, etc). This would be the device if this was the size I was looking for, but I think I’m ruling out anything 11” or less.

13 inches: Is this the sweet spot? Using 13” laptops still feels a bit claustrophobic to me, but it’s certainly better than a 10-11” screen. Is a 13” screen large enough when doing actual work? Would a 13” tablet be too big?

14 inches: Ideal portable size for laptop if you want portability and some screen real estate, but a 14” tablet? Too much? Or perhaps a larger tablet will prove to be great?

15+ inches: I think you see where I’m going with this. I’ve always had a 15” laptop, but the thought of something that massive being held as a tablet … not so sure.

So what do you think? What’s your ideal for a convertible device?

Bonus: What’s the perfect convertible device so far, based on your size of choice?