phd - Should I do a doctorate straight after my master or work for a while first?

I have a BSc in Software Engineering, and I am now doing an MS in Software Engineering (taking more advanced courses and such).

Once I am done with my MS I would like to do a PhD in a software engineering related research topic, but I am not sure if I should get a job for a few years after my MS - or jump straight into a PhD?

With regards to long term goals I do not think I will want to do full-time teaching but I would like to do some part-time teaching (at University level, not picky about graduate vs undergraduate) alongside a professional career.

At this point I am not considering the monetary aspect of a PhD vs. a job. I would simply like to know if one approach is academically and professionally better than the other.

Thank you.

EDIT
Ideally, I would like to work with new, cutting edge technologies, and be an "expert" in my field - hence why I thought of doing a PhD. I would love to perform research as long as I can then apply the results in an industrial setting. At this moment I do not think I am interested in a pure research career.

EDIT 2
Thanks to everyone for their answers, it'l help me a lot. This isn't really a right/wrong answer question so unless an answer gets a huge amount of upvotes I won't be picking an answer.

I guess I should also add what I am currently leaning towards.
Bearing in mind I still have one year to make up my mind, right now I am thinking about one, maximum two, years of work then back to school for a PhD.
...but time will tell!

Answer

Work first. There're many reasons for this:

1. It's not true that you can't work with cutting-edge technologies without a PhD. You certainly can, and it might even be a better use of your time since you avoid the administrative processes that you must do with a PhD. Check out the various graduate programs that employers offer. There might be high entry requirements, but if you can do PhD studies you can clear that bar also.


2. You likely earn more. It's not just for the next 3-5 years that you need for a PhD. If you do a PhD, after you graduate, you'll need to find a job. If you get a job now, you'll already have a job. If you do well you might even command a higher salary in 5 years' time compared to entering the market as a fresh PhD.


3. You might find you don't need a PhD. This could especially be the case if you work with other PhD-holders. You might find that you have the same duties, or that you're already capable of doing what they do. In this case a PhD is not very useful for your career and you might as well stay put.


4. If #3 doesn't happen, then you have a better idea why you're doing a PhD. You know what you want to learn, why you want to learn it, and how that skill is going to be useful for you after you graduate.

It's my observation that people who work first and then go to a PhD are much more likely to have thought seriously about why they're studying. That is a good thing. I'm not saying you shouldn't do a PhD, but you should have good, clear reasons for why you're doing it to avoid possible future regret.