Excel spreadsheets. I have the workbook in a dropbox folder in the cloud for easy access, with backups on my drive. I had Coin Elite and dropped it for CoinManage (LibertyStreet dot com) -- way better interface. Coin Elite was too clunky for me...
I started working with this program after using the other for a couple years. This is way better, data entry is simple, and I can control the details of info that is repeated over and over again. I like the sets feature (like toned Kennedys vs. Mint State Kennedys) and I can modify the screen such as the photos for each variety or add my own photos. All in all it's a much smoother interface
I use Google Drive. More specifically, Google Sheets (within Drive). I can view or edit from anywhere I get internet access. I can access from my smartphone. It's great. One of the great things about using a spreadsheet is you can use formulas to create summaries of your collection. For example, above the columns and rows where I enter each item individually, I have formulas for summing up how many coins I have in total, how many PCGS graded, how many sold, etc.
Just a simple text document. Every time I receive more coins, just add the number to each denomination listed by country and add total face value and total # of coins below them. I don't log years though since I have way too many coins to keep that kind of info. (no special years anyway in my collection, mostly modern currencies within the last 50+ years, I wouldn't see the point in logging years.)
I kinda like Access because I wrote a quick form to do the data entry work. Also can write queries on my inventory and sum up amounts and totals. I wrote a query to tell me how many coins of each denomination I have, another one to tell me what coins I obtained over the years on a given calendar day, another one to tell me how many coins I have over 100 years old, 200 years old, etc.
I use excel and I also keep track by putting them in one of my older north American coin book I highlight the date and put my excel inventory number then what I paid for them if its a newer year book I just write them in under the section of what the coin is like penny dime exc.
The last year or so I changed my inventory method from Excel to a program I found on the internet called Exact Change. It seemed the best for my foreign coin collection as all the other programs were basically all set up for US coinage. It has several good and several bad points. It has been a long hall getting all the info into the program because the Excel headings I kept did not concur with that of the program. Technical assistance has been great but I swear at the program on a regular basis (I did at Excel too so no difference there). I can update all I want and it comes with lots of reports and if I'm brave/stupid I can design my own. I can also export the entire collection/report/series to Excel which I do so I have a back up. If I had to do it over again I would probably stick with just Excel. It is easier to sort, update, etc. The perks of the program is that I get a picture (already included) of my coin so I can find it by sight if I can't find it on Numista or in one of my reference books. I can add, change and how I set up my inventory but it is not as flexible as Excel and it has a lot of features I don't need or wish to have. It works and now I am about 80% happy with it. I changed from Excel because I was having a lot of problems with Excel on my computer and I am no computer nerd. The program ran under $100 and it works so I stick with it. (Note: this is NOT a commercial but my experience and opinion.)
I use excel spreadsheets. After reading all of these replies I am surprised that people keep track of how much they paid for coins (and sometimes how much they sold coins for). It has never occurred to me to keep track of this. What purpose does it serve (except for the obvious reasons if you are a dealer)?
I still use an old check off book that I bought when I was a kid. It's pocket sized and great to have handy at shows. I guess I'll eventually make a spreadsheet, but I do that all day and it would make collecting seem like work. Never mind, I'm just going to keep being old school.
Excel, but I use Numista http://en.numista.com/ to catalog/view/find/etc. coins and they provide the Export to Excel capability. Great flexibility this way, for me, as Numista has nice visual/graphic sort capabilities
I also use an access database.... Part of the fun for me is working with the DB when I don't have enough in the ole coin account to get something new.