Swype is good.
Lightning Launcher= awesome home screen replacement. Once you try it and get the hang of it you will never go back.
swiftkey > swype.
Ulysse Speedometer - speedo app that has a cool heads up display function.
Super Gnes Lite - free super nintendo emulator. Download roms of any super Nintendo game and play it on your phone.
Tapatalk - if you're not already using it, its the best way to surf forums from your phone.
Root it and unlock more potential with:
Titanium backup
AdAway
Portable Wifi Hotspot
Good puzzle games:
Alchemy
Lazors
Bad Piggies
Good set of tools:
ES file explorer
RedLaser
Multi Window Manager
I love messing with Android.