
Here is a quick list of Classes / Packages and programs that seem to make life just that much easier. This is a list based off of things we use daily for quick development of agency type Flash sites. This is in no way a complete list but anyone just wanting to increase their productivity can start here.
Programs:
1) FlashDevelop (PC only – or via VMWare) :/
Use this and easily literally shave days off your coding time. If you don’t use this go with FlexBuilder.
2) Charles (Mac or PC)
Find the root of the real issues when you load dynamic content.
3) Smart FTP (PC only) :/
Quick uploads
Code:
Call a method / function a second later or a frame later. Also has a LoadWatcher for loadProgress
2) Tweener
Some use TweenLite I like Tweener. It always seems to yield the best results. I could be wrong but that’s my opinion.
2) I was wrong – TweenLite/Max
The results speak for themselves – TweenLite/Max vs other Tween Engines
3) BulkLoader (unless you’re using Gaia – see below)
The hotness for loading multiple files and having access to them across your whole project.
4) Papervision
Of course. :-D
* Added from Comments *
Frameworks:
1) Gaia
Steven Sacks has created one of the best frameworks that is to be used on agency style Flash sites. You can have an entire simple flash site up in about 5 minutes or less. (not joking). Site scaffolding, asset loading, browser navigation, page loading, SEO, a place for your transitions (code or timeline) and much more. AS2 and AS3 supported. Check it out!
Are there any programs or code bases you can’t live without?
Let us know.

Definitely wrong on the Tweener part, TweenLite/Max FOREVER!!! :P
nice list thought, didn’t know about Charles. It’s kind of like the Live HTTP Headers plugin in Firefox.
You’re absolutely right Matt. In extreme cases TweenLite/Max whips up on Tweener.
Good catch (editing post)
Without comments for TweenLite/Max engine.
SWFObject?
eclipse and red5
FDT ALL THE WAY!