There really is no general answer to this, though it is widely accepted that money spent on bathrooms and the kitchen is well spent and will serve to increase value. I received an email from a client that recently closed and wanted to know if closing off a dining area to convert it into a bedroom was a smart idea; would it add value? They also wondered if they should refinish the current parquet or install new wood floors.
First I think as a new homeowner you should make changes that will improve your own quality of life in your new home. If in their case converting the dining area to an enclosed space made sense for their use, then by all means do it. If not then deal with it when you plan to sell, assess the market at that time and decide with your agent if it makes sense. Most buyers are going to prefer plank wood flooring over parquet. However if the parquet is in good shape or can be nicely refinished it probably won't be a deal breaker when you sell. If it's in the budget I think you will see a return on new wood flooring and I'm sure you will also enjoy living with it.
There is no question that money spent on the kitchen and bathroom will add value as well as make your home more desirable to buyers in the future. If you are looking to maximize return later on then stick with timeless, classic materials and design. Either way what you install today will be either considered out of style in 5+ years or dated (the idea is to age gracefully). I prefer a classic subway tile back splash in kitchens to the small multicolored glass tiles we are seeing a lot of today. Explore the different counter top materials available, stay neutral and think about wear and tear. Granite was the "it" material 15 years ago, today not so much. Though I still like granite if the pattern is a bit subdued. I always am a sucker for a white kitchen with white carrera marble counters. I know, not the most durable but even well worm with a nice patina, I still love it.
Another thing to factor in is where you live, what is your building like and what are the apartment valuations. If you live in a fairly typical, yet nice post war on the 2nd avenue you may not want to install a $150,000 custom kitchen along with $60,000 dollar bathrooms (especially if you are in a one bedroom!) Stay within the theme of your building (unless you just want what you want and can afford it).
You should also think back to the various homes you viewed..... What did you think of that red custom Italian kitchen? Gold fixtures seem to be back in fashion (why??). Were you tired of all the stainless steel appliances, how important was the flooring type etc. That will be a good guide as you make decisions about renovations in your new home.
NY Time article on which renovations add value.