1) Not half as bad as you Rscott
but I too did 3 months of a split isolation involving majority machines - I did have leg days though. So, wish I'd started on Starting Strength or SL5x5 from day one.
2) trying to shed fat at the same time as doing SS - I think people should just get that foundation sorted before worrying about a 6 pack or "looking" stronger (the numbers are there, you're obviously improving...). So, Wish I'd stuck with a calorie surplus.
3) Squat form (ongoing...) - I was thrilled that the number kept going up, little did I notice that I too was going up at the same time :) eventually I think I would have been "squatting" 200 kilos 0.5 cm
4) Listened to you guys in regards to GOMAD - sure its a good gainer, but for bigger guys I think the 500 tons of lactose is instant fatty :) I do have faith it is ideal for small framed/built people though.
5) Worked Abs - I took what you guys said a little far (i.e. you suggested newbies forget the curl/situp/"forearm" mentality, but you didnt mean avoid them at all costs) and never did a single ab exercise, now I train it somewhat and like the mid section tension it offers.