Development usually begins with an editor or an Integrated Development Environment. The following IDEs are known to support Meteor to some extent:

• Atom - Javascript IDE that can fully leverage Meteor's isomorphic javascript framework. If you want to be able to hack on your editor itself, this is the one to choose.
• Cloud9 - The newest Cloud Development offering that supports Meteor, with a tutorial.
• MeteorDevTools - Chrome extension for Blaze, DDP, and Minimongo.
• Sublime - Light-weight and popular text editor.
• WebStorm - The most full featured IDE currently available for Meteor.

Once you get past your 'Hello World' app, you'll need to start paying attention to your collection and document schemas, and will need some tools for managing your database.

• Robomongo - A longtime community favorite for managing Mongo. Highly recommended.
• JSON Generator - Invaluable utility for generating sample datasets.
• MacOSX Mongo Preference Page - Preferences GUI for MacOSX.
• MongoHub - Another Mongo GUI, similar to RoboMongo. MacOSX only.
• Mongo3 - One of the few cluster management tools around. Able to visualize replication sets. Only downside is it's built in Ruby.
• Mongo Monitoring Service - Once you're ready to bring something into production, MMS is invaluable. Now known as MongoDB Atlas.
• Mongo Express - Web-based MongoDB admin interface, written with Node.js and express

Developing Meteor apps usually means developing multi-client reactivity, which requires collaboration tools. The following tools have proven to be popular within the Meteor community.

• Google Hangouts - Video conferencing and chat.
• Zenhub.io - Kanban boards for GitHub.
• InVision - Collaborative wireframing and prototyping.
• Meeting Hero - Collaborative meeting planning.
• Hackpad - Collaborative document editing.
• Slack - Collaborative project tracking feeds.
• MadEye - Collaborative web editor.
• Screenhero - Collaborative screen sharing.
• Proto.io - Wireframing and prototyping.
• HuBoard - Kanban boards for GitHub.
• Zapier - The best apps. Together.
• Teamwork.com - Traditional project management & gannt charts.
• Sprint.ly - More kanban boards and sprint planning that works with GitHub.
• LucidChart - Online Visio alternative.
• Waffle.io - Trello/ZenHub alternative that integrates with GitHub.

If you want to integrate Meteor with an external API, it's likely that it's going to exposed as a REST interface. We tend to use the following Chrome apps for testing REST APIs.

• Postman
• DHC Rest Client

Online tools:

• Hurl.it
• RequestBin

Most debugging happens in the terminal or in the Chrome or Safari develop tools, which are plenty sophisticated enough for 99% of your needs. However, if you want to debug on Firefox or need extra server debugging functionality, there are a few extra utilities you can use.

• Firefox - Firebug
• Node-Inspector
• Meteor Toys or add directly- meteor add meteortoys:allthings

Texttastic Code Editor - Code editor with syntax highlighting for iOS devices.

Working Copy - Clone Github repositories to your iPad and code on the go.

CodeHub - Browse and maintain your GitHub repositories. Management tool.

iOctocat - Social utility for following Github projects.

iMockups for iPad - Wireframes and mockups. Supports wireframes for desktops and mobile.

Blueprint - iOS wireframing and mockups. Primarily for iOS development, but somewhat usable for web apps.

JSON Designer - Data architecture and data schema design.