It will come down to the screen, storage and android skin in the end, going by what you have said there.
Pretty much just going to echo what Robbo said, the one S is the better phone overall and if you aren't too keen on SE's android skin and want something that will work out of the box, then the S with sense V4 is great for that, you shouldn't be disappointed, IMO sense V4 is very nice, feels polished throughout and the apps/widgets have a very unified feel to it, you don't really have to faff about at all with 3rd party apps etc.
Everything you need to know about the one S is in my review of it (below in sig) and Robbo has done a great guide as to which phone to get, which covers the S and compares it to the other top 2 phones, the X and GS 3:
http://forums.overclockers.co.uk/showthread.php?t=18417660
For storage on the S, you get 10GB for videos, photos etc. and 2.21GB for apps, if that isn't enough for you then the XS is the better option or something else like the GS 2 would be a better device, just to give you an idea as to what the storage is like:
I have over 70 apps installed (including a few games as well), over 700 photos, that also includes a lot of 1080P footage as well as slow motion videos and N64, SEGA etc. emulator ROMS and I have 1.67GB left for apps and 6.10GB left for user file storage.
You also get 25GB of dropbox storage for the next 2 years.
Also something else to consider is the new version of android, jelly bean, no idea if the XS will get it, if it does, then it will be a long wait again no doubt, where as with the S you can be pretty much guaranteed that the one S will get it and a lot quicker than the XS.
The camera on the S is very good (one of the best things about the phone IMO), only let down by slightly jerky 1080P video recording and over saturating reds on auto settings. It is feature packed, more so than any other device and the sense gallery has loads of editing features, which are great.
Again as Robbo said you will have to have a nice long play with both devices and see which one you prefer
