I've been trying to use reading list as a replacement for Instapaper and ReadItLater (just to see if it can be done). The main thing that is missing is the integration with every major app. As far as I can tell there is no public API for the Reading List, but there is applescript support. You can add articles to the reading list like this:
tell application "Safari" to add reading list item "http://jga.me"
which gives you:

If Apple exposes an api, someday, I'd probably use ifttt to sync up ReadItLater and my reading list. Until then I'm trying to think of ways to sync up the two. Maybe just a script that I run on my mac, hits the ReadItLater or Instapaper API and then runs an applescript script for each new item. I'm still kicking around ideas, has anybody else come up with a good solution? I might just have to go back and use one of the 3rd party services, which isn't necessarily a bad thing.
I'm the type of person who like's to have the bare minimum number of windows shown at a time. Whether it's Mail, Safari/Chrome, Twitter, or Reeder, I always like to have that be the only window that is visible on my desktop. To help that, I've written a little applescript that will help me focus on the task at hand:
tell application "Finder"
set visible of every process whose frontmost is false to false
end tell
This script, combined with Alfred, lets me hide all other windows except for the one I'm currently focused on with a simple key combination.
Here's the script as an app: Hide Other Windows
I've been using RDIO as my primary music player for awhile now and, until recently, I had been using Trillian as my primary IM client. Now that iChat in Lion supports Yahoo, I've switched over to iChat. One of the cool features of iChat, is it will show track you are playing as your status. I wanted to see if I could replicate that with RDIO. I've come up with a simple applescript app that will set the track you are playing in RDIO for Mac. It's not flashy, but it gets the job done.
Download: RDIO2iChat App
The Hit List just went out of beta, so I decided to give it a try. I was using Alfred with Things before. I found it was a great way to quickly add something to my inbox that I could come back later and deal with. I've written a small shell script to add tasks to my Hit List inbox. Here's what the prefs in Alfred look like:

Here's the script:
osascript -e 'tell application "The Hit List" to tell inbox to make new task with properties {timing task:"{query}"}'