What's your opinion?

I am currently working on a novel set in the 1760s. Now as part of the research process for this, I've read a lot of what might be termed classic literature from the period and later stuff that harks back to that era.
Yeah, yeah big deal. However, I would value as many opinions as I can get hold of on the following question(s):
How authentic do you think I should make the dialogue?
You see, I know most of you will probably read a lot as well as having written stuff, so where do you stand on this? Do I risk making it hard to read because of all the archaic terms and phrases, or do I kind of give it a feel for the period with sort of psuedo-authentic language? What is your preference when reading something like that?
For example; RL Stevenson's Treasure Island was published in 1833, but it's set in the 1700s, nevertheless it has quite an old-style narrative (which seems quite dated for the 1800s - as though Stevenson was harking back to an earlier writing style for the book). I know it's a literary classic, but that makes things unecessarily difficult I feel. Nevertheless, I don't want to go for the 'Hollywood' totally ignore it syndrome, that's for sure!
And I can't stand it when they have people in the 1700s saying things like; 'Od's bodkins, that's like, totally awesome, I'll wager, milady.'
What do you lot think? If you can point out some examples of modern stuff where you think it's done well, I'd love to know about them.