If you have good credit, then the decision of how much money to put down would be determined by what home you want and what you want your monthly payment to be.
FHA loans only require 3.5% down, but they now have mortgage insurance for the life of the loan, causing you to pay more over time. Conventional loans can be obtained with as little as 5% down; however there will also be mortgage insurance until the loan-to-value ration dips below 80%.
If you want to maximize your value (pay the least amount over time for the home you want, consider putting 20% down because then you don't have an extra few hundred dollars each month going to MI.
Even if you don't have a full 20%, you can use a down payment to decrease your loan amount. So if you are looking at a $200,000 home and you have $20k to put down, you only need to borrow $180k loan amount, so your monthly payment and the amount of interest you pay over time will be less.
Alternatively, if you want to buy a more expensive home, you can use a down payment to add on to what your loan will be and get more home. So if you qualify for a $200,000 loan and you have $40,000 down payment, you've just jumped yourself into a higher bracket of homes - what you can buy for $240k vs. $200k.
The BEST thing to do is to sit down with an experienced mortgage lender who can go over ALL the options, show you actual numbers that can help you make the decision that is right for you! I work with several AMAZING lenders, I'm happy to provide their info to you, feel free to reach out to me for that or any help in finding the perfect home. :)
Starling Real Estate