Way back at the midseason hiatus of season 3, IGN made a list of the all the “Loose Ends” of Lost. They recently updated this list to include the newest info.
It’s a pretty good list, considering it’s from a non-obsessed source. Also the updates are quite encouraging, it’s nice to see how some of the mysteries have been solved over the years.
Check it out here: IGN: Top 50 Loose Ends