Without installing a ROM, you can install a different launcher (the app that is essentially your "home" screen with all the icons and widgets). There are several to choose from. I used to use Apex, but recently switched to ADW. There's also the GO launcher, and others I'm sure. All you have to do is install one, then go into your device settings, More..., Application Manager, scroll over to the ALL list, then find TouchWiz Home. Click on that and scroll about halfway down and there's a button that says Clear Default. Now, when you click your home button, it will pop up a menu asking which launcher you want to use. You can try a different one and choose 'just once', that way next time you click home it will ask you again, until you're sure you want to use that one, in which case you choose 'always'. Then if you want to revert back to Touchwiz later, you can repeat the process and clear the default on whichever launcher you had set as default.
Basically the reason I like to use a different launcher is so that I can customize how many columns/rows are on each screen, to allow for more icons and bigger widgets. A lot of the launchers also support scrolling wallpapers, which I always thought was a cool feature of android, that a lot of companies have disabled in their versions.