I have this in my gitignore file. I think the same principle goes for hgignore file. 

I need to mention that we always install Umbraco using nuget and have nuget restore enabled. If you don't have that maybe you should not exclude the bin folder. Dll's added by packages installed by the Umbraco packages installer we put in a seperate folder and are copied to the bin folder using a post build event.

# Windows image file caches
Thumbs.db 

# Folder config file
Desktop.ini

# Mac OS X Finder Desktop Services Stores
.DS_Store

# git merge files
*.orig
*.BACKUP.*
*.BASE.*
*.LOCAL.*
*.REMOTE.*

# User-specific files
*.suo
*.user
*.cache
*.orig
*.udt

# Build Folders (you can keep bin if you'd like, to store dlls and pdbs)
[Oo]bj/
[Bb]in/
[Dd]ebug/
[Bb]uild/
[Rr]elease/

#Umbraco Folders
App_Data/
media/
packages/

Dave