Like you, after a break of serveral years, I started seriously again with windsurfing in 2007.
My first new board that I've bought late 2007 was the F161.
I still remember that I saw these boards laying in large numbers on the beach of Leba/Poland when I was there in the summer of 2007 at the Allegro Formula Windsuring competition. After I had spoken with a lot of the Formula stars (Steve Allen, Wojtek Brzozowski, etc ..) I decided to buy also such a board. You have to understand that until then I had never seen such a wide and short board. I only knew about the classic narrow boards. So it was quite new for me.
When I started using the F161 in the summer of 2008, I immediately liked it. All the things that were promised, came true. Planing from +/- 8 knots and going upwind with unbelievable angles. Wow !
About the sails, I would advise you not to start bigger than a 9.5 m2 if you are new to Formula + big rigs. I've started off with a 9.5m2 freerace sail (3 cambers). It's a relatively light sail and allows you to comfortably get used to formula sailing, because there's a lot to learn.
Once you get along with it, go for a 11m2, BUT choose a full race / Formula sail !
You will find out that when the wind suddenly picks up, these sails are much easier and longer to control c/w the lighter freerace sails, even in the bigger sizes.
Recreational Formula windsurfing is great fun in low but steady winds, where else you would not be able to sail at all (I'm talking planing of course).
IS87 / IS101 / IS122 / US147