I haven't rooted it yet. I just got it yesterday and android is new to me. Just wanted to make sure that doing the updated wouldn't permanently prevent me from rooting.
I recommend you do the OTA - I did, and it fixed many of the issues I was wrestling with. You will have to re-root, but I had no trouble doing that. It adds a Favorites shortcut that takes you to five or more non-Google markets, and it also adds the Handango market with free and pay apps. Slight performance increase in Quadrant - I currently get over 1450, was getting 1350 before. This also makes Flash work in the stock browser, as well as the YouTube app. However, Flash will not (yet) work in Dolphin. You get the standard Android home screen instead of the bad TnT desktop as default (although you're better off upgrading to ADW or LauncherPro), and you get a bit more stability in the wireless driver.