I watch for obvious reason, but I also watch it for educational resons, tnhe humor and also to get me turned on...I like to be teased, so I guess you could say I'm teasing myself.
Porn does have a bad side affect fir me though...99% of the people in porn are beautiful.  The women are amazing and the men are extremely fit and are packin some major heat. So it makes me feel very self concious about my body and my penis size. It can also set me up for some unrealistic expectation of what real sex looks like and sounds like.  
I have noticed that since I got married, I really enjoy and gett off to one type of porn...blow job vids. My wife refuses to give head.  
Watching porn and being with the providers I've seen, I am starting to feel more comfortable with myself and my desires.

If I am with a provider, I find porn to be somewhat of a distraction.  I would rather turn on, and be turned on by, the lady I am with.  

I watch for entertainment purposes, but not to get specific ideas.  

This website is the best I have seen for ideas on positions and blogs regarding undertaking a new activity.
http://www.sexinfo101.com/

Excuse me, I need to grab a tissue.

I watch porn when I have alone time, sometimes I'll spend the whole day watching it on and off. Watching porn with someone else is hot too. I've never really used it as educational, I get my talents naturally and from lots of practice.  
I like a wide variety of videos, that's why I love the internet. I love women in all different shapes and sizes. The 5-6 minutes videos are great because I can get the variety I need. I get bored watching two people go at it for 20-30 minutes. I would have to say my favorites are deep throat, squirting and FFM. There's nothing better than watching two beautiful woman kissing deeply.

Re: "Can it enhance or debilitate sex with another?"

Both.

For me, the instant benefit of watching mutually appreciated porn is huge. It almost always helps with initial arousal and can sometimes aid in "getting there" for those of us that have difficulty reaching orgasm. So "short term" I find porn enhancing.

However, it can become a crutch as well. Having been in a sexless relationship for ten years, the only sexual outlet I allowed myself was a date with Rosie Palm and the remote control. The visual affect of watching porn, replaced the intimacy of a real women. For nearly a decade, this was my "normal". When I finally got the courage to join this hobby, I found that intercourse and other sexual activities felt very different then what I was used to. In this "long term" example, porn has been debilitating.

The happy ending is, after many dates with several understanding and caring providers (one extremely patient angel in particular) I am almost back to a "new" normal. I still enjoy watching porn, but mostly with a woman now, and not with the sole intention of getting off, but instead to enhance our experience together.

I watch it daily. It rocks me to sleep most every night before I turn off the bedroom TV...

...I've never needed it to get aroused when I meet a provider; she does that just fine just by standing close to me and I anticipate what's going to soon happen. I have used it after round one to help speed the recovery time and I recently used it to show a lady a position I wanted to try that, otherwise, would have been hard to describe. I like pretty normal porn, BJs, girl on girl, and girl-girl-boy mainly. No unusual fetishes. There's so much free internet porn available but I also subscribe to a few member only sites as well as purchase DVDs of my favorite porn series. I also like to attend the annual AVN Porn Awards in Vegas.    I love it when a woman enjoys porn.

.. than in the midst of a strong orgasm during sex with another, when she has completely given up control and lost herself in the moment. So the trick, for me, is to find porn in which those real orgasms occur. Lacking the ability to read minds, I'm quite sure my success is imperfect, but at least the search process is fun. The best method I have found is to focus on male performers who are more interested in getting the lady off than proving their own dominance and virility.  

I have to remind myself that porn orgasms, even when they are real, are still performance. The women are paid to exagerate their response for the small screen. Hoping for the same response in person, whether  in the hobby or out, is a sure road to disappointment. At least it is for me.  

I don't watch porn for how-tos. When I attempted, early on, to implement some porn techniques the reaction was uniformly "Ow!" "Cut it out!" and "Be more gentle." Unless you like porn where the woman is supposed to be hurting, there's a lot of prep work that occurs off camera to get her ready. An exception is some hour long videos that have started popping up recently, Manuel Ferrara and James Deen are doing them, in which you can watch him gradually take her from zero to a hundred. But even there, what works for a young, ripped, hugely-hung fellow is not going to work for me. There are lots of sites and videos, some already mentioned, that are much more informative.  

I've never watched porn with a partner. Maybe some day.

I used to watch porn quite a bit, but since I've started the hobby I haven't watched any at all.

Especially if you offer porn watching appointments Brilove!  That sounds like fun to me.

I'm mostly likely to watch as a sort of preliminary activity when I am seeing an escort in the next day or two.  Most of the rest of the time it's only once in a while but sometimes I do binge on it a bit.

Porn ... to see or not to see ... that is my question ???

I watch porn for the plot and the outstanding script writing.