I've been trying to declutter and simplify my life. After listening to a couple episodes of the Minimal Mac podcast "Enough" I decided one good way to do that would be figure out which apps I actually use and uninstall everything else.
Here is the top of my list - apps I use all the time and that actually make my computer useful. I'm going to leave out the obvious stuff like web browsers unless I have something special to say. There other apps I use but they tend to be things I use to tweak my system or things I just use once in a while.
Apps I use every day:
1Password - password manager - because I can't remember them all. I also use it to store the serial numbers for the apps I own.
MacJournal - my note-taking app/everything bucket of choice. If I want to store something and be able to remember it for later, this is likely where it's going to go.
DropBox - currently the easiest way to keep important files in sync between Macs, iPod Touch, and iPad.
Reeder - the best Google Reader client I've seen on the Mac. I like using an app rather than the web interface.
Pomodoro - great simple Pomodoro implementation. You set the timer for 25 minutes of work or 5 minutes for a break and off you go! It logs everything. I've also been experimenting with an app called Vitamin-R that does that plus block out distractions.
WriteRoom - Minimal text editing. I use this for doing quick notes. The iOS version of this has DropBox sync
Sparrow - the best email client I've seen for a while. They seem to have taken the best features of Apple's Mail app, the iPad Mail app, Google's gmail interface and blended them together. This is something you must try if you have a Gmail account.
YNAB - hands down the best budgeting/personal finance app I have ever used. It is built around the concept for zero-based budgeting - every dollar you have is assigned something to do whether this means buying groceries, eating out, saving for an emergency or buying an iPad. There is an iPhone version and Android version. Both sync over the local Wifi network. The iPhone version uses location services to automatically figure out where you are and guess what budget category the transaction will go in making data entry super fast.
Todo list apps
I'm currently in the middle of trying to decide which one I like best. I've actually ruled out two because of cost - OmniFocus (too expensive & too complicated for what I want) and The Hit List (looks like Things, plus has some of the features of OmniFocus but syncing requires a yearly subscription fee)
Things - great app, very slick for managing your lists of things todo. This one is built on the ideas from GTD (David Allen's Getting Things Done) only it refers to "Contexts" as "Tags." It has built in Wifi sync between the desktop and iPhone/iPad version. The general consensus seems to be that Things and OmniFocus are the two best Mac todo list apps if you don't mind dropping some cash on such a thing. Things is simple and elegant. OmniFocus is no less nice looking, but it does EVERYTHING. Most of the time I see people praising OmniFocus, they are either way more OCD than me or own a business and track everything they need to do out of this one app.
TaskPaper - Tracks your todo lists in simple text files. The iPhone/iPad version syncs via DropBox so you can keep everything up to date.
todo.txt - shell script based tool made by Gina Trapani of LifeHacker fame. There is also an iPhone/iPad and Android version of this that syncs via DropBox.
Xcode - for developing on iOS and Mac apps.
TextMate, MacVim, TextWrangler - because as a programmer, I need a good text editor that does syntax highlighting and I flip between these depending on my mood