Basically if you are working on two lists. You'll want finish checking movies that are on both list. So by being able to filter, let says the 501 Must See Movies with the IMDb 250, You'll be able to find out what movie you'll need to progress on the list at the same speed.

We have signatures for official lists that display our progress on the list, but I think it would be cool if we also had signatures for personal lists.

There are probably too many lists to generate a signature for every list for every user, but maybe you can allow each user to select up to 10 personal lists, and then generate signatures just for those lists.

Like on the "myanimelist" forum, the total length of all views is shown, based on the length it says on the IMDb page for every movie, added up.

Now we see:

You vs. xxx:
1347 - 1005 (checks)
and then compares each of the lists and shows who wins.

My suggestion is also show the total number of lists won and lost.

e.g:

You vs. xxx:
1347 - 1005
80 - 40 - 13 ties

Give the possibility to display our lists on dashboard at the way we want (custom or recent), same as favorite and owned.

Add to settings (on Misc) this option:

Display most recent list on dashboard (instead of custom ordering)

When opening a movies page there is a tab to check what lists it is in, iMC, personal or both.
A nice feature would be the possibility to filter that lists list on lists that I have marked as favorite or watchlist.

I would like to see a hot link to metacritic.com along with the imdb.com on the movie pages. if imdb is the encyclopedia, metacritic is the bible of movies. And with very reasonable reviews across all the web.

I'd love to see statistics or some kind of chart about movies I've watched. Like top 10 actors, directors, or genres I've watched the most, based on my check.

I think it would be great to have the possibility to choose which of your friends activities you want to see. This can be very useful especially for those who have many friends. In my case, sometimes I receive so many notifications, that I have difficulty to see what are my closest friends (in cinematic taste) doing.

Pages with all their movies on. It would be cool not to have to go onto IMDB to find an actors filmography, and which ones I've seen etc.
Also, top 10 actor list?

Remove from charts users that don't check a movie for more than a certain time, like 6 months or 1 year. This will prevent cheaters who register and check lots of movies just to get a high position on charts and then never check a movie again. The accounts are kept and people can still access them. They only drop out of the charts in case of inactivity.

Since I can see on the main webpage the films my friends checked, I would like to comment on these activities, so I can ask him his opinion about it, and so on. I'm lazy to send a private message about it.

In simple words - please add a calendar, in which a specific user or group might add festivals, movie related events and movies (especially the obscure ones) screened in his/her region or country. This might allow other users from the group to find out and prepare for the event, and possibly attend it. This calendar could also be global (visible by all users) with the possibillity to limit the range of events to certain area by the use of tags (country, region, city etc.). It would also be great to allow linking to the webpage describing the specified event.

Add how many people owns the movie among the other stuff like "checked", "favorited", "disliked" etc.

Sometimes I'm watching a specific genre and I'd like to be able to be able to search or filter in some way, from official lists, so I can watch films I haven't checked yet.

create a button who allows you to share the movie you watched with your friends in the social networks, such as facebook

Allow multiply users to edit a list. In addition to the current one-editor-per-list system, list creators could choose to make editing open to anyone, or have restricted editing privileges, where the creator has to approve new editors (similar to how groups work on the site).