Quite the kerfuffle...

 I have technically been married to a British citizen since October 31, 2005...we lived in Florida together for maybe a year after the marriage, then decided to separate. Though we stayed in touch and even attempted reconciliation on several (6 to be exact)occasions, it never quite worked out. We have yet to be properly divorced, and I will just say its because we are lazy about things like that. I started dating yet ANOTHER britboy in march this year. (what can i say? He's utterly adorable, and the former one and i were mentally finished with each other). We do want to get married really, and i have procured a lawyer to dissolve my previous marriage.
The thing is, I haven't formally filed the divorce papers, and I wonder if I have any sort of citizenship(-ish?) rights due to the fact that I have technically been married to a UK citizen for 3 + years.

I know it's a looooooongshot, just wondered.

Nope.  The only way you would have access is if your current husband sponsored you and then you would be able to get to arrive in the UK based on that relationship.  I will assume you wouldn't want nor would he be up for sponsoring you.  The fact that you haven't been living together would be brought into question if you did attempt it.

In order to actually get the citizenship part of it, you'd need to be resident in the UK.  If he had sponsored you and you were still married and you'd applied for indefinite leave to remain and got that and had lived in the UK for 3 years, then you'd be able to apply for citizenship...in other words, there's a residency requirement.