One of the key aspects of Android is that, unlike WP7 and iOS, your device can be customized in numerous ways. You can customize everything from the launcher and lock screen down to the dialer, folders, and icons. If you see an app/category that needs to be added to this thread, please post a link to the Android Market listing of the app and give us a brief description of the app and its purpose.
- ADW.Launcher (FREE) - An open-sourced home replacement that mirrors stock Android 2.2/2.3, but gives you more features and customization. A popular launcher for those who want to make their device look more vanilla (remove Sense/Motoblur/TW/etc.)
- ADWLauncher EX - Paid version of the above, offers more options and customization. Very similar to the free customized ADWLauncher included in all CM installs prior to CM9.
- Go Launcher EX (FREE) - A full featured suite of home replacement options, Go Launcher EX allows you to tweak nearly every aspect of your home screen. It also has thousands of themes that can be downloaded and activated with no tech-literacy required. This has become the most popular launcher on Android.
- Launcher 7 (FREE/DONATE) - A customizeable launcher that mimics Windows Phone 7, but also allows you to add some features to it (wallpaper). Donate version removes the ad banner beneath the application list.
- Launcher Pro (FREE/PAID) - Launcher Pro allows the user to customize as much as or more so than ADW EX, and also has a very large community of users making custom themes and docks for it. The paid unlocker allows for widget re-sizing and for LPP widgets (which look like HTC Sense).
- Go Locker (FREE) - From the same guys who brought you Go Launcher EX, this is a plugin for that launcher and requires the use of it. Different lock-screens are enabled by downloading and choosing themes based on other devices or custom from another user.
- Widget Locker (PAID) - WL is a total lock-screen replacement that allows you to change your lock screen to mimic Sense, Moto Blur, vanilla Android Gingerbread, Honeycomb, Ice Cream Sandwich, and a few others. You can also download thousands of custom lock-screens.
- Chomp SMS (FREE) - Chomp was designed to make the Android SMS client more iPhone-like. If you're stuck on a lousy SMS/MMS client (vanilla's sucks), give this a try. It's easy, fast, and stable.
- Go SMS Pro (FREE) - From the same Go Dev team as their launcher and other products, this is a highly stable and attractive SMS client that offers more options than stock Android, but does not try to simply mimic the iPhone. Does not require other Go software.
- Handcent SMS (FREE/SERVICE) - A fully loaded and customizable SMS/MMS replacement, Handcent will let you do almost anything that you can imagine with text messages. Steeper learning curve and tends to be labeled "bloated" or "buggy," but that's what happens when you have this many features. If you're not happy with other clients and you just want something more, give Handcent a try.