Oh Internet. How will I ever hit my TPS report deadline while you continue to taunt me with your cats playing piano and your talking oranges?
Besides YouTube, here's 10 ways that the Internet keeps me from getting my job done:
Working in the IT industry, I always look for a certain amount of quirkiness in my Internet distractions. Xkcd definitely fits that bill with humor often revolving around science, math, and other academia related areas. Generally okay for reading at work, but occasionally it will cross the line, so be careful.
This web site has a variety of fun items on it, and it's not always comics. Still, it's a great place to waste some time. Each posting often has a collection of captioned pics from the internet that make me smile. Their animated gif postings are usually one of my favorites.
This one is probably one of my older comic distractions, and it continues to amuse me. Office-based humor and irony works for me because I always see a reflection of my working world.

These one-panel "greeting" cards are definitely not from Hallmark. Vintage clip art with a modern sarcastic caption added. Definitely more edgy, so it may be a more appropriate distraction for after work.
Again, not comics, but just a posting of quirky ads that originally ran anywhere between 1880 and 1980. A combination of nostalgia, history, and bad fashion.
These postings consist of one poster, often quite large, that encompasses a single topic. Recent ones have included "Should I Send This E-mail?" and "Geeks vs. Nerds". I often find myself wanting to print these out and post them on my office wall, but is that really a proper use of company resources?
I miss The Far Side, and Bizzaro Comics is one of the closest matches to The Far Side that I've found. Often funny, and occasionally too quirky for me to get.
This website is a great place to find a variety of comics, mostly of the kind you would see in a newspaper. Sometimes the more traditional fair is good for a nice break.
Did I tell you that I missed The Far Side? What I really like about these comics is they are so simple, but they still pack a good amount of strangeness.
When Dilbert isn't doing it for me, I turn to this comic to make me feel a little better about my life. The characters are a little younger than Dilbert, but it seems like corporate ineptitude crosses generational lines.

So, if these links don't keep you from hitting your deadlines, you are clearing not committing yourself enough. Keep surfing!