I'm a huggy kind of guy. I like to show affection and care for the people in my life. Typically, in work settings, I shake hands instead, but I'm wondering under what circumstances it can be appropriate to hug colleagues or others in a professional setting. Also, I know that some Orthodox women avoid physical contact with men outside of their families. How do I know if that's someone's practice, and what do I do to avoid putting those women in an uncomfortable situation?
How about a Hug?
I'm glad to hear you're keeping your impulse to hug in check at work, because it's rarely, if ever, appropriate to have that level of physical contact with a co-worker. If you work in an environment where people are friendly with each other and sometimes share good (or bad) news from their personal lives, an engagement or birth announcement is an appropriate occasion. A death in the family may be appropriate, too, but I think a pat on the back is as effective if not more so. I'd like to think you'll know if it's the right occasion, but when in doubt, don't hug.
If you invite co-workers to a family event outside of the office, or if you hang out with each other socially, you can relax the formality and act as you would with any other friend, but within the work setting, a standard mode of interaction is a helpful policy. At a social event put on by the office, such as a holiday party, there's more ambiguity, but I think social cues are your best ally, and you need to be very aware of the signs you're getting from people. I hate to say it, but, being male, you are potentially subject to a different set of standards for physical contact, and you need to be sure that your friendliness can't be misconstrued as anything more. Also, you need to consider the hierachy at work, and whether the person you're about to hug is more or less senior than you. Hopefully, you have enough to do at work to keep you busy without all these considerations and you'll just avoid the hug.
Orthodox Jews who are shomer negiah avoid physical contact with members of the opposite sex, just as you said. However, some make exceptions for handshaking, which can be considered a "momentary act," putting it in a different category than other kinds of touching. This article  does a good job of explaining this practice, as well as some exceptions to the rule and some suggestions for how to handle potential awkward encounters. If you meet a woman wearing a skirt below her knees, a shirt with sleeves covering her elbows and, if she's married, a hat or wig, it's safe not to try to shake her hand. Even if she's not shomer negiah, she certainly won't be offended by the lack of a handshake.
I would say the same, by the way, about most people and most physical contact. I think it's much worse to be overly forward and too physical than not to be physical enough. I've never missed a handshake, but I have regretted some unsolicited hugs (and don't get me started on cheek kisses from people I barely know). Pay attention to how others are interacting in a variety of settings and how people are responding to you, and I expect you'll be able to determine the best course.