I had the 2008 SL 155, 2009 SL 155(first season with reverse camber tech) and have demoed the 2012 Proto CT 154 and SL 153 and 155. I'm 5'9" 160 lbs (darn holiday food).
Even though I decided to go with the 2012 Proto CT to replace my 2009 SL, I would recommend the SL 158 for you because it is more damp (absorbs vibration and chop better) and still is going to be good in the park for basic jumps and boxes, it might be a bit harder to press it, but really if you know how to press a snowboard, you can do it with the SL, if you don't well you still won't really be able to press the Proto CT either.
Honestly, if you don't plan on going to the park... might want to look at the Heritage as well. Owning/loving a Never Summer Proto CT has become the latest of many internet trends ("It's what the cool kids ride!"). It's a great board, but it isn't the only good board out there.
After a third day on the Proto and more importantly loaning it to a friend for a few runs, I don't think a relatively new rider is going to enjoy the subtle nuances of the ProtoCT.
Also to add onto the "not the only good board out there".... agree here as well.
The ProtoCT is getting a lot of hype and I wouldn't have posted a review if I didn't think it warranted some extra attention. The ProtoCT is a unique board and for those who've been riding a long time, it's design and performance does offer something to genuinely get excited about. That said, the ProtoCT's popularity means nothing in terms of other boards, their design or performance. NS could've just as easily missed the mark completely and no one would be talking about it.
There's been alot of "advancements" in snowboarding, but you have to remember these companies have to invent new and exciting features to keep their product line "hot".
Twin tip -> 3D baseplates -> FatBob -> Baseless -> Capped -> Clip-in -> Carbon -> Aluminum -> Slider > Glueless -> Magnetraction -> Rocker -> RC....etc.
Some of you will recall, most of these "advancements" (and the many I left off) were little more than hype. My opinion is what we're seeing with the ProtoCT is proving to be a promising evolution in design and materials. I suspect next year's NS lineup will show heavy influence from the ProtoCT's popularity.