The anti-glare gives a better sense of what colors naturally look like, and being a web designer I would think that is pretty important. Most people use matte screens so what looks good on your screen might look under-staturated on their screens.
Personally I prefer the anti-glare, and unless you didn't really do anything but watch a lot of movies I don't see why you wouldn't get it. Glossy is useless for about anything else IMO. Really though, personal preference should outweigh anything else, just be careful when color reproduction is an important factor, it's not like you could opt for an IPS display or anything.