A generic .gitignore file, specific to the work I generally do these days (2015ish). Modify as needed before using.

.gitignore

###### Generic Stuff ######
*.bak
*.old
*.swp
*.log
.DS_Store
.Trashes
Thumbs.db
archive/  # old stuff I'm just not ready to toss.
notes/    # my dev notes, copy from client, project descriptions, etc.
vendor/
node_modules/

###### SASS/COMPASS Specific ######
*.sassc
*.cache
.sass-cache/
compass_app_log.txt

###### .NET Specific ######
*.dll     # most scenarios you don't want to push the dlls.
*.suo
*.user
*.webinfo
*.exe     # usually don't want exes in my repo.
compiled/
bin/
obj/

###### Packages -  usually there's no need to push archives, unpack them instead. But modify if needed. ######
*.zip
*.tar
*.rar
*.7z
*.gz
*.iso
*.jar   # that random time when I end up in the JAVA world.

###### Expression Engine/Codeignitor/Laravel - might need to modify the paths. ######
*.env
*.env.*.php
system/expressionengine/config/database.php
system/expressionengine/config/config.php
system/expressionengine/cache/*
images/avatars/
images/captchas/
images/smileys/
images/member_photos/
images/signature_attachments/
images/pm_attachments/
sized/
thumbs/

###### WordPress ######
wp-config.php
wp-content/advanced-cache.php
wp-content/wp-cache-config.php
wp-content/backups/
wp-content/backup-db/
wp-content/cache/
wp-content/upgrade/
wp-content/uploads/
wp-content/blogs.dir/

###### Perl ######
*.o
*.bs
/pm_to_blib

###### Vagrant ######
.vagrant/
boxes/
*.box