I have been thinking about installing a new ROM, like CyanogenMod (most probably), but thought it would be a mess to return to stock ROM if I messed it up, plus, last time I checked, not all features are guaranteed to work (camera, tethering, ...).
Now, my question is not about how to backup the old ROM, because I found another solution: as my phone is rooted, why not remove the stock launcher, the stock music app, stock browser, all the Samsung Software Update and Holy Quran and Samsung Apps and Swype and all the apps Samsung forces me to use? These are easy to back up (in case), and I can replace them with a browser of my choice, ADW Launcher (CyanogenMod's one), music player of my choice, keyboard of my choice, etc.
So what does a custom ROM offer more than just custom launchers and widgets and looks? Or is my option "utopia"?
Note: I'm not sure if that matters, but I'm on a Samsung Galaxy Fit GT-S5670, Rooted Android Froyo 2.2.1
Another Note: I read this question and its answer, but the answer there only states things that could be done with a home replacement app...
UPDATE It seems nothing can't be done with apps. It's just easier and faster and more stable to use a custom ROM, that is if the ROM for your device is stable enough.