I think Microsoft should give people the choice as to buy with or without touch cover for both the 32 and 64 models, but we've got what we've got.
Certainly, with the ability to add up to 64GB of extra storage, choosing the lower capacity model won't ever really be a problem. Of course, as others have pointed out, apps can only ever be installed to the internal storage, but unless you plan to really cram the thing full of the more space hungry apps like games, then that won't be a problem.
These days, even with the higher capacities of storage available, HD movies (for example) can chew through space pretty quickly, so you have to manage that - but then the same would be true of the competition also. Beyond that, I wouldn't worry too much about storage.
One final point, is that the Surface has Windows - this is the Ace up it's sleeve. You can browse the network much more easily than on any competing tablet platform. So, what I do is have a large NAS drive on my network, shove all my media on there, and then I can access it wirelessly around my home on my Surface! Work's great, and means my stuff is available on all my PCs and devices. Consider the cloud too - sign up to Skydrive (free) and get some space up there, integrates with Surface really well via the app!