Yeah, the iPad or other tablets won't replace a netbook/laptop for everyone. For my type of IT work/support, web access is the #1 need, followed possibly by Remote Desktop (Windows) or SSH (Linux). Physically plugging the iPad into anything isn't a requirement here.
As far as video over 3G, it has to meet certain
bitrates (64-440kbit). The initial ABC app didn't support downgrading to that level, but as of yesterday with an update, it now works fine, and looks decent enough to be watchable. Youtube videos tend to look worse, as they appear to be downgrading quite a bit.