TP - I've used a number of Linux distros over the years, but I've settled on Ubuntu in the last couple of years, because it's arguably the most popular 'consumer Linux' there is, so I feel there are generally fewer compatibility issues, it has a decent
repositories, and more support in places like
http://ubuntuforums.org/. I've also run Damn Small Linux from a USB drive as a way of accessing the Internet more securely from public computers overseas.
The two main problems with various Linux distros as far as I'm concerned are support for certain hardware can be patchy, and installing certain applications (via 'packages') can sometimes turn into a geek nightmare. If you never run into these issues, all well and good, but if you do, they can be absolute show-stoppers. For example, around three years ago I installed Ubuntu 6 on a Dell Inspiron portable - it wouldn't recognise the built-in wireless and the only way to fix it was to 'recompile the Kernel' - which is about as scary as it sounds. Ubuntu has improved a lot since then, and with the community support there's a lot less chance of having to get your hands dirty when things go wrong, or running into an unfixable problem. For me, right now it comes closest to passing the 'it just works' test, although it different people may have different experiences depending on their equipment.
It's worth testing the CD-based Live versions of various distros. If you just want to see what they look and feel like (it won't guarantee hardware compatibility on a natively installed operating system), you could try a system such as the
Mokafive Player, which has a number of distros available as virtual machines (
http://lab.mokafive.com/List) (some of these are a bit old now though).