If your not sure at this point, it's probably best that you don't. The main benefit of course being custom ROM's, kernals and the like but you'll want to be sure before you do it as you'll be voiding your warranty in the process. For me its not that big a deal, I've had it since launch day, what am I going to do, take it back?
Rooting also satisfies an in-explainable need in some of us to just tweak the damn thing, make it better, make it ours. It's like a guy who adds custom headers and other mods to his car...would the original manufacturer ever service under a warranty, no. Would someone who is willing and wanting to install such a mod really care, probably not.
At this point, ("end of life" for the Inc as far as Verizon is concerned) there are loads of ROMs that have virtually every bug worked out of them that are fairly similar to stock but with some enhancements like no bloatware and tweaks to the UI that make it more efficient. You can have a phone that is very familiar to you but is better than stock cause its not loaded down with garbage you wouldn't use and/or you can stick to stock and just remove (with some knowledge of what to remove and what to leave alone) what you don't want. Then there are ROMs that include new feature like the new Sense 2.0, and ROMs that are plain vanilla but are Gingerbread based and thus more advanced than Froyo just without HTC's sense UI.
It's all about options and all about what you want to do. I've got friends with iPhones that are perfectly content to have ONE ringtone to choose from for their email and would never consider jailbreaking, or friends that have Inc's that love sense, love Froyo, are happy waiting for Verizon to debug/test Android 2.3 and would never think about voiding their warranty just to gain, what they would classify as minor enhancements.
To me, the answer was easy, it's my phone, I'll do as I please. I'm not using it with mal-intent like tethering stuff on the sly, I'm just customizing my phone to what I want with out Verizon or HTC's consent...hey I paid for it, what's it to 'em right?
Long and winding response but just figure out what you want out of your phone and go from there.
edit: If your worried about OTA updates and one starts rolling out you would like to opt into after you've rooted there are a couple very good guides on how to un-root.