Choosing a linux distribution, easy or hard to learn, will finally get you into its core. My suggestion would be to aim for the one that will make you comfortable with all of them and that would be the hard path. If you learn Ubuntu, you will know Ubuntu. If you learn slackware, you will know linux. Other than that every linux distro has a full featured Desktop Environment so you got the usability part solved. You could check Slackware, Zenwalk, Salix, Fedora.

Linux gained a significant name in the market.AS operating system it can be downloaded anywhere,from mobile to supercomputers and also it had so many latest features associated with it which gives you more thing to access.

My apologies, but that's a much more interesting question than 'What is your favourite distro' (the OP probably didn't think that's what was asked, but the hundreds of 'which distro for me' threads usually have elements of that, rather than an answer to the question asked).

@EricTRA/pixellany (I'll not call that race and it is essentially the same point)
While it is true that distrowatch covers more distros than it would be convenient to download (by an order of magnitude, or so), Distrowatch doesn't even have pages on every distro out there; there are some that are in long-term/temporary hiatus and some that are too new and possibly even some that are too specialist, to have made it (yet?), so the problem is rather bigger than that. Not that distrowatch doesn't show the problem to be big enough...

@EricTRA
Hey! No fair...that's ubuntu (more or less) with different User Interfaces and you could take one of the 'buntus and just install other GUIs. Well, apart from mythbuntu/Ubuntu Studio which may do a relatively trivial bit of fiddling with some of the kernel parameters, although the stuff the user interacts with aren't much impacted by those changes.

@afullmetalwar
Ubuntu is actually a good suggestion for user friendly, but user friendly does sometimes fight 'idiot proof'.

OK, assuming that it was Ubuntu 10.04 and kubuntu 10.04 that was a waste of (some) time and a waste of (some) bandwidth. If you install an Ubuntu, you can get other UIs for that version by using the package manager, and you don't download the whole nine yards over again, just the UI (although that won't exactly be tiny).

In fact, from where you are now, a good question to answer would be 'Which User Interface(s) do I like and want to use?'. An answer to that question will push some distros up the list and others down, as some specialise in one particular UI (the 'buntus are not quite mainstream in giving the versions with different UIs different names...you could argue that this is only semantics, but it does cause confusion).

...and people who liked the Ubuntu kind of thing, also liked Mint and Mepis, more or less.

...and distrowatch evens bans some distros (not that it's a big loss).