Shawn,
Great to hear that you're getting back into windsurfing. It's better than ever with all the new equipment.
Ya know, I would look for a relatively wide board in the 115L range for Utah. That's a good intermediate volume to start at. It'll serve you in most conditions and with any sail really. Some might disagree and suggest 135+, and I don't knock that size board, I'm just saying if I were to have ONE board here it'd be in that range. I know that a lot of people are selling really good boards in that range. Compare prices on Windsurfing Classifieds like windance etc. Later a great second board is one in the 95L range. When you do get your board, make sure to get out to the mornings sessions at Grantsville. You'll progress very quickly out there and if you ask anyone for advice they'll give it to you. People don't really want to impose their advice on you usually out of courtesy. But if you ask we're all happy to help.
Most people, on a North sail either out of Provo Boat Harbor (a little bit bigger swell on a full north) Pelican Bay Marina (a little closer to SL)... On a south, mile marker 19 as far as Utah lake goes. Deer Creek is always having people out. Check out
www.livelakeview.com for live cams on many of the locations.
Good luck and we'll see you on the water.