I went to your user info page and looked at the communities listed on there... hope you don't mind. :) I figured, hey, if you talk about things that are really interesting to me in one community, chances are you're probably talking about other things that are really interesting to me in other places too, right? That, and I was kind of hoping to find a bunch of other people who were asking similar questions.
Anyway, I think I can help answer two fundamental questions you're more or less asking here: #1, what happens when you die?, and #2, what's the deal with various spiritual entities out there (what are they, how do they effect us, and so forth)?
To answer this question from a "scientific proof" perspective, the best approach I've found is to delve into the realm of out-of-body experiences. Now, as a personal note, I must say that I haven't gotten OBE's to happen myself just yet (or, perhaps, more accurately I could say that I don't actually remember having had any). But I do accept OBE reports from all sorts of different, independent sources as valid and reasonable evidence of "what's really going on" in the spirit realm and such. By that I mean that they're all remarkably consistent and the logic of their explanations makes a great deal of sense to me.
Unfortunately, I have to recommend YET ANOTHER book to you, to answer this question for you:http://www.amazon.com/exec/obidos/tg/detail/-/006251671X/qid=1126852590/sr=2-1/ref=pd_bbs_b_2_1/103-3128595-5036647?v=glance&s=books
There are quite a few OBE books out there, but I think this one is the best I've found to explain all sorts of things about OBEs, relate them to histories of existing religions, and answer "the deep questions" that you're asking here. Technically, I could give you my answers and/or understandings of all these things in detail as well, but directing you to this book seems more generally efficient.
It's also good to have a perspective of the universe as a continuum of various vibration levels when you're trying to materialize objects. ;)
Oh, and I've connected various spiritual things into a bunch of blogs I've written on my own LiveJournal page... most of my longer posts end up tying whatever subject I start with into some deeper spiritual perspective on the matter eventually, so of course you're welcome to read any of those that may be of interest to you as well.