If I can't find a 128 soon, this is what I may do. I still have my laptop and desktop for most of my legacy apps. Honestly if it wasn't for the staggering difference in speed between the Pro and the RT, I'd keep my RT. I just find myself getting frustrated as heck with how slow it is at times. I've played with the Pro a few times now and have never seen one bit of lag on it.
I've yet to find anything that'll slow the Pro down. I'm almost tempted to install After Effects just to see if that will do it
I think the 64 Pro - the recovery partition + a 64SDXC would be viable for someone who doesn't have a lot of storage needs. If you subscribe to Office 365, it comes with 20GB of extra storage (in addition to the 7 you already get) for SkyDrive, so if you're around a fast connection enough, you can offload stuff you don't use as much. 32GB usb keys are pretty cheap now as well.
I got the 128 because I always overbuy. I would have picked up an 8GB/256GB model for another four or five hundred dollars if they made it, but I'm pretty convinced now that it would have been a waste for what I use it for.