I have a 20D that takes ef-s glass, and a 1d mk11n that doesn't. I have both bodies so the 1 ef-s lens still has it's use. But I will change it eventually for a L lens.
So If your considering changing to a full frame or 1.3 think carefully, but also think how likely it is you really will make the change to full frame. Most likley your regular lens will be a ef-s anything else wont be, eg telephoto, primes. So you'd only have to change one lens to replace the ef-s.
You are only likely to need an EF-S at the wide angle and you won't lose a shed load of cash when you come to sell because there are plenty of cropped sensor users out there so demand is still high. Also if you don't buy now you will be restricted with the type of shots you can take currently
it deepends when you are thinking of changing, yes the glass will be easy to sell, but why buy and then have to sell in say 3-4 months when you could spend the money on your new camera??
sorry to interupt
but does anyone know if the sigma 105mm macro will work on full frame? and will it still be good