While some of us are talking about Linux is there really much of a difference between all the distros? I have only ever used Ubuntu so i wouldn't know 
Yes...and no.
when I first started using linux back in the dark ages, one of the great things about it was stability and the ability to custom tailor the kernel to EXACTLY what hardware was in your comp and turn on all sorts of compile time flags to squeeze out every last ounce of performance (we all compiled our kernels by hand in those days). I actually often used X for my GUI. NOwadays we hardly worry about how much memory we use or how much unnecessary cruft is included with the kernel we don't need - we just want the spinny cube and the wobbly windows and to be part of the cool kids.
Now, having said all that "git offah mah lawn" stuff, Karlos is right - the distro basically handles all the crap that sits above the kernel and delivers it to you. Some do it on release cycles (ubuntu, most others), some do it rolling release (Arch, Gentoo as well I believe), some use special packages (apt and rpm), some use binaries (arch, slackware), some compile every damn piece of software (Gentoo). Some force you to have an Out of Box Experience with all the bells and whistles, some make you build your system by hand from a command prompt.
As I run an "old" P4 as my daily coding machine, I like it to be as lightweight as possible while still be "modern". I run Arch and vascillate between DWM and XFCE for my windowing manager.
