touch, newest ipod- it has thousands of down-loadable apps including games, entertainment, reference, news, fitness, etc. also can store songs (which one you buy depends on storage 8gb being lowest), stores videos, notes, whether, email pick up, and photos, web browser (safari ) also is fully touch screen operated. iphone is the same as the ipod touch except has the feature of a phone and a little bit more storage and a better web browser. the ipad is a enlarged ipod touch except it is the concept of a small laptop, notebook computer. in fact many reviews state it will be the next generation of laptops and eventually will take over net-books it also is bigger, more ststability and has a little more apps available to it, like a bookshelf,were you can upload your favourite books and read them on your ipad.
the iphone is different because there is i believe over 200,000 apps out there most being useless allot being very use-full