First you've got to find out what you need a computer for. Different people need a computer for different reasons. And once you find out what exactly you need your computer for, there are many alternatives other then clogging your computer up with tons of extra software.
I need my computer for work
If you need your computer for work, you can always use google docs and spreadsheetsThis is a free service google offers that lets you do word processing, spreedsheets, and a new comer to this service is now google presentations. It will only be a matter of time that google will also offer a nice database program. And also when you download your saved data from these services you can choose to download it in a number of formats.
Do you need to manage your money and expense. If you ask me the safest way to do such a thing would be do online bank strait from your banks website. And if you have more then one bank account with several banks sign up for all of the banks online banking plans. Usually these are all free to do. However if you just want to be able to access one site and manage all your bank accounts, you might want to try Buxfer.
If you truly need an OS for any other things that your business does, you may want to try You OS However there programs aren't compatible with other OSes. Which is a major bummer.
But I mostly use my computer for photos, music, and videos
Well for photos there are several choice you can choose from.
Googles Picasa (only supports JPEGs to my knowledge)
And if you want your photos to be private and not viewed by anyone then you can always set up an FTP Server. Just go to your favorite website hosting company and purchase some disk space.
For videos you might want to try
Rip Way (they do everything. You can upload webpages, photos, music, and videos)
For music I can only think of Rip Way
But what about games?
Games! Games! are you out of your mind computers are tools, if you want to play games you should get a game console. But if you still insist on playing games. You might want to check to see if your current OS has the games you like installed by default. If it doesn't you don't have to install anything else, just go to Games.com
And that is about it.