Honestly, the best place to start would be deciding what about LEGO interests you. For me, being a structural engineer, buildings of any sort draw me in, as do landmark structures (read: Tower Bridge). Therefore, I mostly stick with modular purchases, grabbing random sets here and there for either MOC purposes or because the set looks cool/is cheap.
I realize that last line sort of contradicts my idea of finding a starting point, but that's exactly it - a STARTING point will help you grow your collection around what interests you.
If you think you're going to get into the MOC'ing (creating your own shit from the piles of bricks you have), you can start to explore sets based on that. If you are simply going for display, the larger ($$$) sets are more suited to your taste. If play is a factor, the smaller sets work wonders. These cheaper sets ($5-30) offer excellent parts and pieces to build your MOC inventory.
I know the info above is probably something you have little to no use for at the moment, but sometimes, just thinking about what side of LEGO intrigues you will help. Sarcastic or not in your comment on "where to start", there's a bizarre rush when opening that first big LEGO set in ages.