Source code: http://www.github.com We could host our own server, but github is really convenient and our SDKs are open source so its easier.
Workflow & Issues: http://huboard.com/ Given we use github, huboard makes it easy to mange the issues
Build: http://jenkins-ci.org/ and https://github.com/capistrano/capistrano Such a nice setup, we host our own jenkins server, I have seen some links above to Travis, might give that a spin.
Tickets & Wiki: http://www.uservoice.com Its a love/hate relationship with uservoice. They make some things easy, others are so arcane. I'm adding in a wiki article right now with some images in it. But uservoice doesn't let you host an image, so I put it into an S3 bucket, add the link to uservoice and there is a security error. I go back to the bucket, reset the security settings and uservoice is caching the image error and wont let me add the images, so I need to edit the source. So hard for something so simple.
Team Communication: https://www.flowdock.com/ We were using Campfire, but we like flowdock much better. Threaded conversations are still tough, I actually miss Google Wave. We had 1 wave a day, it starts to grow on you.
Log Aggregation: http://graylog2.org/ Very cool once you get it all working together
Server Metrics and Application Analytics: http://www.graphdat.com We dog food our own product, so it's our servers on the homepage..
Some other notable candidates:
'your personal website': http://backstit.ch/ handy to monitor a couple of feeds
'tech news aggregator': http://skimfeed.com/ nice way to skim some news