First, welcome to the forums!
Second, Rooting is definitely worth it. Free wifi tether makes it worth it by itself. Customization, themes, CPU control, different roms and kernels all are added bonuses. I work with someone with a "jailbroken" Iphone 4.....from what I have seen, android customization is miles ahead of what you can do with an Iphone. With Apps2sd you can do almost the same thing you can with an Iphone as far as the amount of apps and media you can use. Different launchers give you the option to change your dock on the bottom.
I started with a Sprint Hero, rooted it, upgraded to an Evo, rooted the day I bought it......just upgraded my wife to an Evo....rooted and running custom rom and kernel the day she got it. Never looked back.
As far as roms, you need to look around and try them out. There are so many options, it is personal preference as to what you like and don't like. The Rooting for Dummies thread explains flashing and has a link to a list of roms available. Any questions, there are many here that are will to answer them and help out if you run into trouble.