Offline D2E
I have been offline for a couple of weeks because of a change in my coordinates. So I haven't touched D2E online for ages... might just start off the game offline Single Player.
With an application I downloaded for offline item muling (ATMA), it should not be much of a problem to do item runs and build characters with good items I find.
With the duping problem, and the fact that I play in single player games online too anyway, I think single player offline is a good option.
Yes, levelling up is slow and might be a problem, but it is fun as well.
I would suggest (and try) working up with a character like a poison/bone or summoning necromancer or a sorceress, then do NM difficulty item runs, get medium quality items, then get going with stronger character builds which need these items, but can kick more ass. Then do the high level item runs. And the beautiful thing is that you have your characters forever... they will not get deleted when you don't log on for 90 days, and your hard work won't be wasted.
Happy gaming.