Roger-
Firstly--since we've had these discussions on the bosses and our roles previously--thank goodness you're considering getting out of there!! Good for you! Its a bold step and a first step towards finding something to make YOU happy--and thats a good thing!
I wish you the best of luck in your search and hope we can all come together and give you some fine assistance. Looks like a great deal of wonderful information has been passed along already-fabulous!
I would definately practice interview questions if its been a while since youve done this sort of thing and go over all the positions on your resume and find a honest yet not revealing way of a positive spin on those, its hard but it helps.
If you get to an interview and give these answers and someone wants more and more information in that avenue you can always do your best to sway the conversation with positives. Ive had some interviewers however that were crazy people and gave them as little information as possible--thats something you get a feel for. Maybe you can have someone help you practice?
Being in a position for over 5 years shows loyalty already, dont worry about that one. I like the examples Phoenix gave on large vs small companies.
You can also go with company environments-well groomed professional sales vs casual manufacuring for example. You're lucky enough to have one of those positions where that works in your favor wherever you go
Dont forget to use companies nearer and dearer to your home location as a plus as well.
If you go into an interview prepared you can nail a great many things and take any twist around. Its funny really.
Look at the job description very closely. If they are looking for an independant, reliable applicant well then--your current employer could be a micro manager even after a long relationship (if you've gotten that person thats delving deep into it that is). In that way while you put a negative sway to the current boss its not looked at from an HR point as negative in the situation, they are looking for your positives-and this is one of them.
Really cant stress enough though that ANY time you have something in at all negative to say you spin positive back over it to end your statement with. Practice Practice Practice.