Rooting just gives you access to parts of the phone that otherwise locked up. For me, the important effects of that are:
I can run Titanium Backup to keep my apps and there data backed up.
I can run RomManager to get a complete backup (nandroid backup) of my phone to include all apps, all settings/contact ringtones/everything.
I can run free wireless tether.
I can install custom ROMs.
Right now I'm running Axiom 2.3 ROM (there are a number of other great ones to choose from), but because I'm not running a theme or any MODs on top of the ROM, my screen shots would look the same as yours. The phone is just faster and smoother. The ROMs are also running Android 2.0.3, which by the time Google releases it to Verizon,and they release it to you, the ROMs will probably already be on 2.0.4.
Whether you choose to install ROMs or not, if you're going to root your GN (which must also include unlocking your bootloader), the sooner you do it the easier it is. This is because to unlock the bootlaoder (you only do that one time), it wipes everything from your phone, including anything you have on your sd card. At least what the GN sees as your sd card...the directories you see when you plug your phone into your pc, like pictures and music. Great instructions can be found here:
http://forums.androidcentral.com/ve...ock-bootloader-root-verizon-galaxy-nexus.html
http://forums.androidcentral.com/ve...backup-restore-install-roms-galaxy-nexus.html