One of the main problems when upgrading to any new OS is to get the peripherals to work. Microsoft took a lot of heat when people could not get their printers, network cards and what not to work with Vista. In my world drivers are the main responsibility of the device manufacturer and not the provider of the operating system, with that in mind I will not bash Ubuntu completely for the lack of drivers in the Linux community.
To my desktop I have a Canon MP450 multi-functional printer, an external hard drive and my IPod. I also use USB-thumb drives and two digital cameras on a regular basis.
Using the Canon MP450 original software was out of the question since it requires Windows. To get the printer to actual print is impossible. Ubuntu recognized the Canon MP450 and displayed it as an available printer, but when you send print jobs to it nothing happens. I went to the Canon website trying to find some drivers for Linux, no luck. After some poking around the net I finally found a working driver called TurboPrint. TurboPrint is actually commercial software and costs 29.95 Euros; you can however try it for 30 days.
Since the MP450 is a multi-functional printer I thought it would be nice if the scanning worked. Ubuntu comes with a pretty neat program called Xsane Image Scanner. Xsane recognized the MP450 and I was able to scan, it even worked faster and was more efficient than the software that came with the printer. With the original Windows software you had to scan the images to an image-editing program, it slowed the process down dramatically. In Xsane it is possible to get previews of the scanned image and edit the scanned results.
The external hard drive and other USB-storage devices worked surprisingly well. When you connect a thumb drive an icon will appear on your desktop, it could not be easier. When I briefly used Linux several years back I remember USB support being very limited, if it worked at all. It is great to see that the Linux-community has worked those problems out.
Getting my Ipod to work with Ubuntu is a different story. When connecting it a small Ipod-icon appear on the desktop, if the Ipod is formatted using FAT32 instead of HFS plus it is possible to manage MP3-files just as any other USB storage device. But the strength with the IPod is ITunes, and since Apple has not made a version for Linux you will not be able to use it. Tough luck, but there are a few Linux alternatives. One of them is gtkpod, which claims to be a GUI for iPods. The program keeps track of your songs, ratings but more importantly has the ability to import and read your ITunes DB from the IPod.
Obviously the whole IPod process is not as easy as in Windows or OS X. Of course Apple has no real interest in releasing a Linux version of ITunes, when looking at the market share Linux is not that far behind from OS X. For Apples perspective it probably makes sense not to give the Linux community ITunes, Linux might even catch-up.
A main-usage for many family computers is online-banking. Many banks have platform-independent solutions, such as dongles generating passkeys. They will work with Linux; some banks have other solutions such as card-readers or certain programs that needs to be installed. Chances are that many of them are not compatible with Linux, so before moving over to Ubuntu it might be good to check with your bank.
In the old days most devices had problems with Linux and were lacking drivers. It is clear that there have been improvements since then, most devices actually worked somewhat. However it is also evident that there are still more work to be done, the real question is however who is going to do the work. Most hardware manufacturers are not providing Linux-drivers for their devices, some will never do it. Why? Because Linux is still a small operating system compared to Windows. Other device manufacturers, like Apple will probably not provide working software and drivers since Linux is a competitor to their own OS X. I think that drivers and getting devices to work is the main obstacle for Linux to reach popularity and a sizeable market-share.