For people that might be interested in what you can do (maybe haven't jailbroken before...) here's what I did.
1) Download Absinthe 2.0.4 for windows.
2) Run the the .exe
3) Click jailbreak
They recommend clearing your phone to increase the speed but it only took me 5 minutes (without removing anything). Once completed, it will add the 'Cydia' app to your screen, which you can use to download other apps & utilities.
Now onto the interesting part.. the apps I've installed today, and what they can do for the phone (all are free):
1) f.lux: Just like flux for the desktop, this will modify the temperature settings of the screen to adjust according to your timezone, being much easier on the eyes at night.
2) IconRenamer: Rename any icons. I like this because I can take something like 'Samsung TV Remote' which looks like 'Sams...ote' on my phone and change it to "TV Remote"
3) BrowserChanger: This allows me to install Google Chrome as my browser, and open all URLs by default in Chrome instead of safari (So I get all my synced bookmarks, etc. Opening a link from another app like Alien Blue, will use chrome instead of safari, as well as 'home screen' shortcuts)
4) ColoredKnob: Allows you to change the 'scroll to unlock' icon colour and size.
5) MissionBoard: Triple-Home-Click will open a MissionControl style background-app selector which shows screenshots of the apps in their current state on a nice background.
6) Torch: Adds a nice little icon next to the clock on the lock screen to enable flashlight torch.
7) Weather Icon: Causes the 'Weather' app to display the actual weather with icon and temperature. Runs based on the first weather screen, which can be set to 'local weather'.
8) Zeppelin: Customise the carrier logo. You can choose from things like the apple icon and countless others, which I like instead of having a giant "YES OPTUS" on my screen.
9) Adblock: Blocks ads.
10) SBSettings: Allows me to swipe my status bar to quickly toggle options like 3G / Wifi / Brightness. etc. You can also download themes to make this look more like a iOS native application.
11) NoNewsIsGoodNews: Disables the Newsstand icon which I have NEVER used in iOS.
12) Springflash: Enables me to double-tap the power button for a torch.. Not really necessary but I like it.
13) YTOpener: Automatically opens any youtube links in the new Google YouTube app. Works awesomely well.
14) LSMusicGestures: Adds swipe gestures for music controls to my lock screen. I love this as I dont have ipod controls on my car stereo. It allows me to do things like swipe to skip song, or double-tap to pause/resume a song. This is awesome as it means I no longer have to look at the phone, or try hitting the tiny buttons on the screen while driving.
Doing all of this took about 30 minutes, doesn't do anything to make my phone look 'tacky', and had no issues at all.
Can't believe I havn't been doing this since the day I got my 4S. I had previously tried using some of these apps on my 3G but it was pretty slow. Everything is nice and slick on the 4S though.