If you're not sure, go out and try different jobs...
I've worked in an R&D lab
Council offices
And now work on the highways installing, commissioning and repairing traffic lights.
Every time I've changed jobs, knowledge wise it's been a step backwards - I no longer need to know how circuits work at component level, no longer need to be able to pick and choose components, no longer need to do day long testing procedures on each section of a circuit like I used to do in R&D.
In the council I was overlooking a lot of highway electrical systems - traffic lights, tunnel systems, bus information systems, VMS signs etc etc...
Now I only deal with traffic lights.
Some people say I'm mad for going backwards - many people ask why I'm doing this job with the qualifications I have as I'm hugely over qualified.
Why do I do it?
No boss standing over me
Company car (not the perk it sounds though!!)
No office (except the pile of paperwork in the back of my car)
No-one to shout at you if you're 5 minutes late
No car parking issues (just set out cones and an arrow

)
And I enjoy the work!!
I enjoy work that is hands on. I enjoyed R&D because of this, however there are not many jobs out there for analogue audio r&d tech / engineers.
The council was not hands on enough - too much time at a computer, and not enough depth when I did get hands on... the council were too quick to pass problems on after initial diagnosis - frustrating when you're used to fixing.
My current job involves biolding, testing, fixing, commissioning, and if my boss gets his way will also involve maintenance.
So, when you look at it, although I've gone backwards in some respects, I've found what I like doing... for now at least!!!