I've been mostly paperless for a couple of years and love it. I get overwhelmed by paper and it's easier to search in the computer.
I started with a portable hard drive and scanner. I created folders for each year and sub folders in those years. I put documents in the right folder as I scan them.
----> Retail Receipts -----> Nordstrom
----> Work -----> Pay Stubs
----> Travel -----> Location -----> Photos
I decided to use a portable drive specifically as my "filing cabinet" in case my laptop ever crashed. Plus they have a lot of room and I can just plug it in wherever I need it (like when I get my taxes done).
The key is deciding on the structure then properly naming and filing all of your scanned documents as you go. It can get really overwhelming if you don't have a system.
I keep the current year on my Dropbox (with a copy on the hard drive) and also back everything up to the time capsule.
It's becoming really easy to return things to retailers if you pay with a debit card. They can generally pull up your shopping history just by swiping your card or using your phone number.
If not, I've printed scanned copies of receipts a couple of times and haven't had a problem.