* A place to deploy their code (bare metal box in a datacenter, hosted VM, Heroku, Engine Yard, etc.)

* Revision Control System (git, svn, mercurial, etc.)

* Monitoring (page me if X, Y, or Z)

* Metrics (Google Analytics, Cloudkick, etc.)

* CC processing (Chargify, Spreedly, Cheddargetter, etc.)

* Wiki or other documentation / information dissemination tool

* Blogging (posterous, wordpress, etc.)

* Bug tracking (github, trac, etc.)

* Email (gmail, yahoo, hosted Exchange, etc.)

* Other communications tools (Campfire, IM, etc.)

* Project management tools (Basecamp, Flow.io, etc.)

* Others?

Each of these has a price. Either they cost you SaaS money, or they cost you time (as well as infrastructure cost) in learning how to roll your own, deploy it, maintain it, back it up, et cetera. The cost for all of these can quickly add up, and yet if you roll your own, you may be leaving your area of expertise, and you're certainly not focusing on the heart of your own product.

Which infrastructure costs (listed above or not) have you decided are worth paying for as opposed to rolling your own, and why?