If you root it correctly, (and its difficult to mess up) you wont need to re-do anything on your phone. I personally prefer a Command Line style, which is how I did mine, of course yours would have different file names but still same idea. (I have the original Droid)
Spoiler adb devices
adb push c:\droid2root\rageagainstthecage-arm5.bin /data/local/tmp
adb shell
cd /data/local/tmp
chmod 0755 rageagainstthecage-arm5.bin
./rageagainstthecage-arm5.bin
adb devices
adb shell
mount -o remount,rw -t yaffs2 /dev/block/mtdblock4 /system
exit
adb push c:\droid2root\Superuser.apk /system/app
adb push c:\droid2root\su /system/bin
adb push c:\droid2root\busybox /system/bin
adb shell
chmod 4755 /system/bin/su
chmod 4755 /system/bin/busybox
mv /system/recovery-from-boot.p /system/recovery-from-boot.p.disabled
mount -o ro,remount -t yaffs2 /dev/block/mtdblock4 /system
rm /data/local/tmp/rageagainstthecage-arm5.bin
exit
Or you can get an app that will automatically root your phone for you. Universal Androot is a good one I hear. (never used it myself, Command Line is much easier for me, no flashing or anything)
Alternatively you can download a rooted .sbf file and flash it to your phone, or a rooted Update.zip file.
It depends, really there are only a few "great" benefits I use my rooted phone for.
1) Tethering (A bunch of my friends during class use their Ipod Touches to connect) It also works well when your main home ISP is down or you are downloading large files on a PC, using all of the bandwidth and you want to jump on some Xbox Live.
2) Overclocking CPU/Underclocking to save battery life
3) Taking Screenshots
4) Wireshark.....yeah
5) I created a Swap file to help out my limited RAM on my device. It made the phone run noticeably faster.
I havent really gotten into themes or anything like that yet though.
Just make sure to do some research on your particular phone, and what others have done with it. And most anything you do can be reversed. Since its a Droid 2 by Motorola you can always download a stock .sbf file and use RSDlite to flash back to normal.
*Also a note on CDMA chipsets, they cannot handle data and Verizon network access at the same time. So say you are tethering to an Xbox, and are in a party, if you receive a text or a call, it will kick you from the party/game. Usually it will reconnect to the party/game after the text comes through or the call is completed.