OK, here's the fix, I know OS's, Linux or Windows or Mac, have a way to separate each user's stuff but I am going to tell you a better way. Buy a portable bookshelf disk drive for each member in the family. You can work the system a number of ways but for privacy and security nothing beats your own drive. Newer PC's will even allow you to boot from a remote drive, this means the PC can have say Win7 on it and the remote drive can have Ubuntu Linux on it. So when you want to Ubuntu, plug in the drive and drive.
Also if you got kids and your laptop looks it, buy a remote keyboard and mouse, this will channel the sticky fingers away from your laptop. Now, now, compare the cost, $50 remote keyboard and spilt milk vs $700 laptop and spilt milk, aah, you get it!
Personally I don't like those digital picture frames. Besides looking like an old fashioned wide matted photo, they barely do a slide show. I would take a wimpy laptop, turn the screen backward so that you can see it when it is closed (for the coffee table or wall mount) or on a stand (on the mantle), then use a remote keyboard instead of a built in one. I can hide the keyboard, the picture frame is a wonderful 10"-15" diagonal, and I can have sound with my pictures. The thin PC frame looks sleek and modern. You can do the same similar thing with an old and/or cheap PC but recycle that old CRT monitor and get a LCD display.
I have a question, how many PCs can one have for one's self and not go mad? I now have three and they are driving me mad just thinking about it. Two Ubuntu and one XP (the laptop). I guess it is time to dedicate PCs for different uses. On my network I can make one a server for file storage or a multimedia machine and plant it in the living-room TV cabnet. This is an old dilemma you know, ever wonder about the madness in a clock shop during a daylight savings time change, same thing. Add to this the personal computer vs the computer you share with the whole family.
It's kind of a weird thought to have so much potential in a PC and restrict it for a specific use, but lets replace the word limit with focus or dedicated. However, if you need to rearrange or rebuild or reprogram your devices, the potential is still there. it's not wasted, just redirected. So, if you have your computer setup as a multimedia center to be accessed and used by the whole family, you probably wouldn't want to use it for personal internet adventures unless you're home alone, but you can. With my laptop, I can now sit in the livingroom, watch TV and converse with my wife (she misses me!) instead of hiding in the computer room.
Watch TV?? Yeah, through the multimedia center. That depends on what you have connected to it, cable, satellite, internet (like YouTube), DVDs, CDs, what ever source that can be played on the TV through the computer, including regular broadcast TV stations. With a lot of what is deemed as entertainment these days going up in quantity and down in quality, I go to the library for DVDs and download stuff of interest. The big question though is can you do this stuff with Linux???? Yes you can! There are several Linux applications that do multimedia. Miro, and MythTV are the ones known to me, there are more, like Moovida (looks hot!).
If you don't like what is on broadcast TV, cable, yet you want entertainment, news, you can be choosy, picky and downright discriminating about what comes into your house.
I tell you the DIY cult is alive and well. There are still backyard tinkerers, mechanics and stereo/video buffs, extreme gamers and home theater fanatics. You can even turn you garage into the Lowes but the marquee violates zoning laws and a ticket window! Come on!
But why DIY when you can buy a pre-packaged, ready to plug-in and use system? Because you can take it all apart and rebuild it better, with the ready to plug-in and use systems you are stuck with what you get. The caveat, mileage may vary, so check it out before you commit.
Well, I got to go, I'm eying my garage for a major renovation, a mini iMax, pass the juju-bees.