We upgraded our downstairs moulding only. We had the 2" builder grade moulding too. It completely transformed our house. I felt like I moved!
We spent about $3000 for the moulding alone and the labor was a whole lot more but it really will depend on how big your house is and the type of wood you select. (Our baseboard was made up of 2 pieces of moulding 1x6 and picture frame moulding. We also went with 2 piece chair rail. So although the contractor just had to measure once they were cutting 2 pieces of moulding for every wall). We went with paintable wood that we painted ourselves. (Huge job and nothing like painting a wall but I recommend you do it before installing it. You will have to fill in the nail holes and touch up the moulding though). We changed the door entrance moulding (ie front door, foyer to LR, LR to foyer, LR to DR, Foyer to Study etc. but that contained 14 pieces of various types of moulding for one side. We also added a 5" flute moulding around the doors, crown and picture frame moulding to the walls and some of the ceilings). 2 contractors were here for about 6 weeks. It was a huge job. Much bigger than I initially anticipated. I got a lot of my ideas from the the website hometrimwork.com. They seem to be having an issue with their website but you can check them out on facebook. Their website has over 1,000 before and after pics of moulding ideas.
FYI...we went to a lumber yard and they delivered. Also each piece we bought was 16' long so there was much less waste than if you bought the 8' or 12' pieces at Lowes.