Some cool android apps( must have android apps)

First thing I observer on the galaxy is that it did not come with an explicit file explorer. It takes all the trouble in filtering the files by their types and putting them in their respective app folders( music, videos...). I personally did not like the idea though. then went my first search for a good file manager an almost unanimous choice of most users, Astro File Manager .
The browser that comes with the phone doesn't look good with not a number of options to me. if you're a fan of tabbed browsing go for Dolphin Browser .
Task manager is something you will need as a lot of apps wont offer you an exit button and they keep running in the background, an unnecessary drain of battery. There are many taskmanagers out there as always in the android market. I chose Advanced Task Manager among them and I am happy with it.
Spare parts is a nice app which describes the battery state, and gives a lot of options to check which app or which service is using the battery etc..
Mixzing is a popular audio player with nice features like song suggest and album art download.
Chump SMS and Handcent SMS are two alternate apps for the default messaging app provided with the phone, both of which have their own pros and cons. It all boils down to what you want from it.