Yes.  There's nothing wrong with saying: "I'm excited about your offer, I feel I can really make a contribution here; there's just a few issues on which I feel we need to discuss.  Based on market conditions etc. ... I feel that X days of vacation a year would be an acceptable number."

Yes.  Not just an offer, but an accepted offer, on which you're done negotiating.  And then resign gracefully, no matter how much you hated your job. 

To negotiate?  No.  To choose?  Inasmuch as possible, yes.  I explain, "This sounds like a really exciting offer, and I'm really flattered.  I want to take the time to consider it, run it past my spouse, financial adviser, etc.  I'm also discussing with other companies, and I want to see all my offers at once so I can be sure to opt for the job that provides the best fit.  I expect to be able to give you an answer no later than ___."

That you have multiple offers, yes.  That you expect them?  Not necessarily. 

No, I wouldn't tell them what they are.  If there is a job I like better but their offer is not as good, I would negotiate until I'm happy with the offer ("I feel the fit is really good, but your offer is not quite in the range I'm looking for; do you feel you can do anything to improve it?" 

Maybe even, "I'd really like to work for you, but I feel a $Xk difference with your competitor is pretty significant.

There are many good books out there that help with the process; my favourite is Martin Yate's Knock 'em Dead 2008 book (ISBN 978-1-59869-165-8), because it contains excellent tips for the entire job search process and takes to the readers as competent professionals, not a bunch of children.