There is good adventure for beginners in Eberron Campaign Guide, I would go for it, and follow it by Seekers of the Ashen Crown. Khyber's Harvest(free at drivethrurpg) is also set in Eberron.
I voted for 3.5 but it was hard choice. I really like 3.0 with some minor changes(Monte Cook ranger as default 3.0 ranger for example). It has only few supplements but it's just enough. 3.5 has better writen rules but class and rules bloat is sometimes overwhelming.