iPad1 – everything. Had it since shortly after they came out (3yrs now). It’s my main portable device (work and personal), replaced my laptop, I have a desktop machine.
Web browsing, posting stuff on here and elsewhere, email, work document reading and markup (via iAnnotate), voice calls via Skype (no camera on iPad1), notes (sharing via iCloud), music, photos (keep lots of favourite stuff there plus upload my camera photos and share iPhone photos via photo stream, movies on flights (outstanding), facebook, youtube and vimeo (midweek mini movies etc), works very well with Apple TV to drive content into TV when I want large screen format from youtube, vimeo, bbc iplayer etc), redbull tv for mtb, etc etc. It doesn’t have a sim card but I use it with my iPhone for web access or better still now I got a 3 mobile wifi unit which is excellent (3 is much faster than T-mobile and I can share with connection easily) – used when on the commute (35 min train ride) or when travelling or away from home with no WiFi.