I think CM7 is a great base vanilla 2.3 Android ROM, My first Android phone was the Nexus One so I really got use to the vanilla Android... I traded my Nexus One for the EVO and Sense isn't bad.. Compared to all the other programs dressed over Android it's probably the best but I just missed that vanilla feel to Android... I love being rooted and I am not rooted to get anything past Sprint (Free Tether) I just loved the Vanilla feel and the ability to remove all the bloatware that Sprint throws at the phone.. I will never use the NASCAR, NFL or Sprint Zone Apps preinstalled.....
I think the best part of being rooted is just the ability to switch between different ROM's and get a great feel for what you really want to use. I think by far CM7 is the best (IMO) I have ran a few other sense and non-sense based ROM's as well as different Theme's and what not....
It will require a little more "WORK" in a way as you have to keep your radio's and what not manually updated as you wont get the auto updates from Sprint as you will with a stock right out the box ROM..
Good luck my friend.... Just read and read some more and make sure your ready before you do it... I flipped flopped for a couple of weeks before taking the plunge and I wouldn't go back...