(advance apology for 3meopcp blather-may edit later)
Raas: So you didn't disagree that christianity was edited and mainstreamed by constantine/nicea, just that it was designed as a system of control (i only said it could be thought of that way; maybe it could just become a system of control through ).
My feelings on christianity (fwiw): when i imagine what i might think if i wanted to be a christian, i'd definitely want to focus in on the most authentic stuff from before rome got hold of it and discard the later stuff which is mostly dodgy imho. There's some core stuff which i'd stick to (do unto others..., love your enemy, turn the other cheek, maybe even the vague concept of heaven (but more like nirvana (or talking heads' version)); the rest is surely just bullshit that's accrued over years due to the various special interests (eg roman and medieval european authorities), and is too contradictory and simplistic to bother with.
However, what you're left with if you do this is pretty much the same as all other religions when you do the same thing with them (as shown in Huxley's Perennial Philosophy or Karen Armstrong's Great Transformation). You then see how similar all these religions actually are at their heart - eg the golden rule (do unto others as you would have them do to you/do as you would be done by) pops up in various religions independently (cos it's like common sense i suppose), though confucious is first i gather; and Rabbi Hillell (a pharisee!) stated it some time before jesus if you want to get all competitive about it.
My main problem with christianity is the ridiculous exclusivity it sometimes has. "Only through jesus will you find heaven" excludes an awful lot of very nice people (not to mention extra-terrestrials) from this "heaven" and to say that if you weren't lucky enough to have found the 'word' you're doomed just seems nasty and cruel - a bit of a medieval holdover. A religion claiming to be a contender for explaining reality with the sophisticated philosopies and cosmologies that are around (eg marmalde's or colt dan's above posts) using that sort of materialistic 'only through jesus' criteria in the infinite universe we're in is absurd to say the least; leave out or modify that specific exclusivity, and the christian metaphysics can be a lot more convincing and interesting as a cosmology i'd suggest (eg look at teillhard de chardin/omega point).
imho - Christianity should get some humility and just say: you can find heaven through faith in jesus, but as long as you're following some basic rules of niceness (do unto others yada yada), you may also find it through faith in krishna...or maybe through buddha, or LSD, or PCP, or science, or whatever, - if you were like that as a religion (or a person), you'd find people wouldn't mind having you round so much 
As for what you were saying about islam - you can't judge the depth of their religion by some random on the interweb surely? (there's some sort of irony there somewhere). Alongside the mainstream, Islam has rich mystical and metaphysical traditions in some ways more sophisticated than those of western christianity. For wisdom, have a look at some of the Sufi literature for instance (mulla nasrudin)
The religion is philosophical, not a scientific journal on metaphysics. It is issues of good and evil which are important to us and give reason to our existence on this planet, and this is what the book fully addresses.
