Once you root, you do not have to flash a rom. Correct.
However, it is not recommended that you simply root your device and keep it like that. The reason is, once you are rooted, your device is basically exactly the same before, with a tiny modification to allow certain functions. Though it is open to doing many other things (ROMing, overclocking, etc) it is still a phone with the stock firmware, and as soon as an OTA (Over the air) update rolls out from verizon, you will be prompted to update to that. If you DO update using the OTA update, it will patch your root access and you will be back to square one (in fact, you will be at square 0, in other words, you will be updated to a newer version, one that it may not yet be possible to root. you've gone from a rooted phone, to a new non-rooted version, that is not possible to root yet). The way to make sure you are not going to accidentally update with the OTA, is to flash a new ROM. Once you flash this, you are safe from verizon's corrupt plots to limit your phone's functionality.
If you plan to delete some preinstalled apps, change the notification bar and system icons, and you do not know about coding/modifying the android OS, you will definitely need to install a custom ROM. That is, unless you know how to open a command line and type in the correct things to get the phone to accomplish this without having to ROM the phone (very complicated to learn and you will be very likely to brick your phone, especially if you have no knowledge of what you are doing). ROMing your Droid will be much safer and much easier for you to accomplish what you want.
best of luck and thank you in advance for your efforts.
