Here is a list of our favourite development tools:
<strong>Version Control</strong>
<a href="http://git-scm.com/" target="_blank">Git (Distributed Version Control)</a>
<a href="http://code.google.com/p/tortoisegit/" target="_blank">TortoiseGit (Windows UI)</a>

<strong>Continuous Integration Management</strong>
<a href="http://www.jetbrains.com/teamcity/" target="_blank">TeamCity</a>
<a href="http://www.sonarqube.org">Sonar (Code Quality)</a>

<strong>Development IDE</strong>
<a href="http://www.jetbrains.com/IDEA/" target="_blank">IntelliJ IDEA</a> (Java)

<strong>Configuration Management</strong>
<a href="https://puppetlabs.com/puppet/puppet-enterprise/" target="_blank">Puppet</a>

<strong>Build Tools &amp; Package Management</strong>
<a href="http://maven.apache.org/" target="_blank">Maven</a>

<strong>Profiling</strong>
<a href="https://visualvm.java.net/download.html" target="_blank">VisualVM</a>
<a href="http://www.yourkit.com/overview/index.jsp" target="_blank">YourKit</a>

<strong>Production Monitoring</strong>
(which version deployed to which environment).
For example, Nagios, OpenNMS and HP Open View.

<strong>Logging</strong>
<a href="http://logback.qos.ch" target="_blank">Logback</a>
<a href="http://www.slf4j.org" target="_blank">SLF4j (logging abstraction)</a>

<strong>Testing Tools</strong>
<em>Low Level Tools (Code Level)</em>
<a href="http://www.junit.org/" target="_blank">JUnit</a>

<em>Mid Level Tools (Functional/Component level)</em>
<a href="http://www.soapui.org/" target="_blank">SoapUI</a> (Functional Testing: Create mock data services)

<em>High Level Tools</em>
<a href="http://www.seleniumhq.org/" target="_blank">Selenium</a>
<a href="http://fitnesse.org/" target="_blank">Fitnesse</a>
<a href="http://www.rallydev.com/test-management" target="_blank">Rally</a> (Agile)

<strong>Web Service Testing</strong>
<a href="http://findbugs.sourceforge.net" target="_blank">Siege</a> (Load testing - Linux)
<a href="https://www.owasp.org/index.php/OWASP_Zed_Attack_Proxy_Project" target="_blank">Zed Attack Proxy</a> (Web Application penetration testing)

<strong>Code Tools</strong>
<a href="http://www.joedog.org/siege-home/" target="_blank">FindBugs</a> (Code Analysis)
<a href="http://www.mythicsoft.com/agentransack" target="_blank">Agent Ransack</a> (Multiple File Search)

<strong>Document Databases</strong>
<a href="http://www.mongodb.org/" target="_blank">MongoDB</a>

<strong>Graph Databases</strong>
<a href="http://thinkaurelius.github.io/titan/" target="_blank">Titan</a>

<strong>Graph Visualisation</strong>
<a href="http://keylines.com" target="_blank">Keylines (Web graph visualisation)</a>
<a href="http://thejit.org" target="_blank">JavaScript InfoVis Toolkit (Web graph visualisation)</a>
<a href="https://gephi.org/">Gephi</a>

<strong>Mobile Development</strong>
<a href="http://www.playframework.com" target="_blank">Play Framework</a>
<a href="http://www.sencha.com/" target="_blank">Sencha Touch (JavaScript)</a>
<a href="http://www.gwtproject.org/" target="_blank">GWT (Java)</a>
<a href="https://vaadin.com/home" target="_blank">Vaadin (Java)</a>

<strong>Graphics</strong>
<a href="http://www.getpaint.net/" target="_blank">Paint.NET</a> (Bitmap Editor)
<a href="http://www.inkscape.org/en/" target="_blank">Inkscape</a> (Vectors Editor)
<a href="http://www.colorschemer.com/" target="_blank">Color Schemer</a>
Pixel Ruler

<strong>REST and OData frameworks</strong>
<a href="http://restlet.org" target="_blank">Restlet</a>
<a href="https://jersey.java.net" target="_blank">Jersey</a>
<a href="https://code.google.com/p/odata4j/" target="_blank">OData4j</a>

<strong>Authentication</strong>
<a href="http://oauth.net/" target="_blank">OAuth</a>

<strong>OSI PI</strong>
<a href="https://pisquare.osisoft.com/docs/DOC-1101" target="_blank">PI Developers Club FAQ</a>
<a href="https://pisquare.osisoft.com/inbox" target="_blank">PI Square Login</a>
<a href="https://pisquare.osisoft.com/docs/DOC-1101" target="_blank">PI Developers Club FAQ</a>

<strong>Useful Tools</strong>
<a href="http://www.teamviewer.com/en/index.aspx" target="_blank">TeamViewer</a> Online Meetings
<a href="http://notepad-plus-plus.org/" target="_blank">Notepad++</a> with XML and JSON extensions (json)
<a href="http://www.scootersoftware.com/index.php" target="_blank">Beyond Compare</a> (Code &amp; Config Comparison)
<a href="http://www.xmlvalidation.com/" target="_blank">XML Validation Tool</a>
<a href="http://getglimpse.com/" target="_blank">Glimpse</a> (Diagnostics platform for web apps)
<a href="http://www.trilead.com/Download/" target="_blank">VMX</a> (Virtual Server Management)
<a href="http://wixtoolset.org/" target="_blank">WIX</a> (Windows installation package builder)
<a href="http://fiddler2.com/" target="_blank">Fiddler</a> (HTTP debugging proxy)
<a href="https://wappalyzer.com/" target="_blank">Wappalyzer</a> (Website Technology Scanner)

<strong>UI Software</strong>
<a href="http://balsamiq.com/" target="_blank">Balsamiq</a> (Wireframing Software)
<a href="http://www.crazyegg.com/#." target="_blank">Crazy Egg</a> (Eye Tracking Software)

<strong>Charting libraries</strong>
D3
gRaphaël
Highcharts
AngularJS
Telerik Kendo UI
aCharts
Cubism.js
Dojo GFX
dygraphs
Flot
Flotr
Flotr2
Google Chart Tools
Envision.js
Javascript InfoVis Toolkit
jqPlot
jQuery Sparklines
jQuery Visualize
milkchart
RGraph
Rickshaw
Timeplot
GraphUp

<strong>Business Tools</strong>
Intranet - <a href="http://www.simpleintranet.org/">Wordpress Simple Intranet Directory </a>
Accounting - <a href="https://www.xero.com/au/">Xero</a>
Project Management - <a href="https://basecamp.com">Basecamp</a>