ADULTERY and GREED:
Ok, these aren't disputable issues, just my analysis of the source of a problem that is present in everybody's lives, including the Christian church.  Both of these sins arise from the same premise: people are always seeking to be happier than they already are, no matter how good their circumstances might be.  Even if they have a nice family, a beautiful and loving husband or wife, a decent house, cars, etc., everything that someone could/should want, they must have more.  Were they happy originally?  Sure, even though they will try to convince themselves (and others) that they weren't.  If they truly weren't then it was probably because they were busy looking at other opportunities in the first place.  I'm not saying that every relationship is perfect.  On the contrary, I think it's obvious that none of them are.  Life is about being happy with what you're given and recognizing that it's not usually half bad.  In short, making the best of it, being content [Philippians 4:10-12].  It's not about trying to reach the next level of happiness from your current state or some sort of imaginary euphoria.  Play the best hand you can with the cards that you're dealt.  Now, one could argue that this could lead to laziness, but I'm not talking about avoidance of achieving additional levels of accomplishment, only being content with your present status and not putting self-fulfillment above pleasing your family and God.  I am also not talking about cases of abuse, poverty to the point that you cannot meet the basic needs of food, shelter and clothing, or extreme laziness.

ALCOHOL:
Based on the overall usage of wine in the Bible, with it even being endorsed by Christ as his first miracle [John 2:1-12], I cannot find a good reason why I should not drink.  Yes, I've heard the argument of some Christians that Biblical wine was just grape juice and not fermented, but this makes no sense at all given every Bible verse I've read, not to mention simple logic disputing this nonsense.  If it were otherwise, then it would not speak negatively of getting drunk, for drunkenness would not have been occurring with over-indulgence of grape juice.  I absolutely do not advocate drunkenness and whenever I drink alcohol, it's in moderation.  In the 7 years that we've been together, my wife can attest that she has never seen me drunk (well, maybe once).  My normal rate of consumption is probably about 1-3 drinks per week.  I also recognize that some people cannot control themselves from over-indulging, being pre-disposed to addiction.  These individuals should obviously stay away from any drinking of alcohol, lest they fall into temptation.

On a side note, because I am an active participant in church activities, I need to be exceptionally sensitive to avoid offending anyone or to not cause any fellow Christians to stumble.  I also recognize that some non-Christians can look upon drinking as a secular activity and condemn any Christian who is seen doing it as a hypocrite.  Both cases are due to gross mis-information, but the cause is irrelevant.  As annoying as it is, I need to take efforts not to offend others when drinking in public.

ATTENDING CHURCH (a.k.a. "organized religion"):
I've heard it said that "I don't need to attend church to get to heaven".  That is a true statement.  However, there are many benefits which can be gained by attending a good church.
1)  It's Biblical - There is no category in the New Testament for a Christian that is not involved in the body of Christ, the church.  If you don't go to an official "church", then where else do you gather with other believers to be nurtured, worship God, pray together, help other Christians, and evangelize to the rest of the world (see table below for verses associated with each church purpose)?
2)  Fellowship - spending time with other like-minded individuals can provide the following:
    a) Encouragement - knowing other Christians face the same struggles which you do in everyday life.
    b) Support - having Christian friends can provide assistance (time, money, concern, etc.) during times of trouble or need.
    c) Conviction - other Christians' lifestyles and conversation might make you aware of things in your life that you didn't realize you needed to change or improve upon.
3)  Inspiration - a good pastor will provide instructional insight in his sermon which you can apply to everyday life.
4)  Knowledge - a good pastor can also provide teaching and understanding of God's word that only someone who has dedicated their life and their education to learning about it can do.
5)  Worship - allows you to spend time praising God through song and prayer that you wouldn't otherwise do.

HOMOSEXUALITY:
I strongly believe the majority of homosexuals (see the end of section for exceptions), especially male, were born with this predisposition.  My logic is supported by my own experience with predispositions toward women.  There are certain aspects of the female form that I find more attractive than others, and certain preferences and situations that arouse me sexually more than others.  These were evident from an early age, perhaps around 9-11 years old.  Perhaps earlier.  There wasn't anything in my childhood environment that would have caused these inclinations toward my specific sexual preferences.  They just materialized at a certain point in time.

Even if one doesn't have a tendency toward any sexual oddities, there are plenty of other "issues" that different people seem to have from early on in life.  However, I also think it's our job as Christians to overcome our natural sinful desires, whatever they may be, and that God can assist in these matters.  Of course, this may be something that the individual will struggle with their whole life, some days more than others.  I believe that a gay person could focus on the emotional love of the opposite sex, and allow it to dominate and overcome the natural sexual desires.  Sex, in the context of time spent together, is such a small part of any loving relationship.

For non-Christian homosexuals, what reason would they have for not being gay and from the secular standpoint of the rest of the world who cares if they are?  In fact, from the non-Christian point of view, why not let them marry, as long as they're not hurting anyone else in the process (like leaving a previous spouse or taking children with them to live with their partner)?  They are consenting adults choosing to share their lives together.  From the Christian point of view though, this would make it more difficult for them to consider choosing Christianity at some point in their lives because that would not only mean a change of lifestyle, but also a painful divorce procedure.  I don't think that gay couples should be able to adopt children either.  It should be obvious that a child would be better off with both genders as parents.  But then again, perhaps it would be better than the alternative of getting sexually abused in (in rare instances), or otherwise shuffled through numerous foster homes.  

Additional notes are below.

• For a great, non-religious point-of-view against gay marriage, check out Kathleen Parker's article here.
• Another really good article is from Thomas Sowell here.

• Obvious exceptions to the rule of predisposition would be individuals who were distressed or abused emotionally and/or physically by someone (the opposite gender, relative, parent, etc).