I came back to Lego after nearly 40 years of dark ages... I first re-completed the old sets of my childhood, then started a nice collection of Pat. Pending classic sets and parts, i.e. things issued between 1955 and 1974.
The transition to modern Lego happened when I found a 5867 set in a garage sale. The set was cool in itself, but the trigger was the 23 alternates of Nathanael Kuipers, that I have reverse engineered. I can only recommend to any Lego fan to 1) buy a 5867 set from Bricklink, 2) rebuild Nathanael's models 3) buy his books to check the solutions. It will change the way you build with Lego.
After a while, I stumbled upon the Architecture Studio issued by Lego in 2013. The concept was exactly what I needed - I have an unexplained fascination for Lego white parts - and was an excellent basis that only needed to be expended.
I have thus purchased hundreds of white and transparent parts : I have now over 3000 white parts and can create what my fantasy tells me to do...
My favorite subject is architecture, but I build cars too, plus... anything I can find inspiring!
I am currently working on Technic cars. Started with simple pull-back MOC's, and rapidly jumped in the Power-Functions domain.