To add something to what Psycho said...
Web Design can, just like Web Development, get you a nice and quite well-paid job, and it is nowhere near being bored during the job. However, Web Design also involves generally graphical skills (Photoshop, etc.) and, most importantly, a good imagination of how your ideal website would look like (unlike the Web Developer who cares for the actual functionality of the site).
I cannot really speak about qualifications or any experience in jobs right now, though, as I am right now only getting ready to start searching for jobs myself.
As Web Developer, you will certainly have a more "challenging" job experience (if you're not currently using CMS's, that is) due to the complicated nature of all programming languages for the unskilled eye. If that's what you like to do (I do, certainly), then go get yourself a nice degree. I'll do just that, possibly a general degree for Computer Science or something more specific like a qualification for online programming languages, though I believe my nearest university does not offer such course.
Help my post helped you out deciding a bit