I have a lot to say on this matter, so bear with me.
I have served in the Army Reserve for 15 years.  I joined as a Military Policeman, one of the only job specialties in the service where women serve in combat roles right along side their male counterparts.  I spent the first 12 years as enlisted and the last 3 years as an officer.
In that time I have personally served with two gay females, both who were open about their relationships.  The male soldiers generally bonded with and protected both of them and no one had issue with it.  I also work with a gay female and her partner who both successfully served in the Army as soldiers, got out, and now serve admirably and honorably as Army civilians.
I am also sure that I have served with gay males, probably in the conditions most of you fear (open bay showers, shared sleeping quarters, etc.).  Statistically, it is probably impossible that I have NOT been in that situation and it made no difference.  I am, however, secure in both my masculinity and my sexuality to be able to handle the situation, regardless.
Here's my general opinion on the matter for those that assume a gay male is attracted to them uncontrollably.  Have you ever worked with a female co-worker that you know was attracted to you, but you weren't attracted to her?  I have, several times.  The only way to deal with it is through honesty and professionalism.  No different in dealing with a gay co-worker who takes a liking to you.  If they harass you, then its harassment, period.  Otherwise, if you can't handle it, it amounts to your own fear or bigotry or inability to see it from the other side.
Also, soldiers of both genders are increasingly progressive with their sexuality in today's military.  Young female soldiers tend to be up front about "female issues" and their sexuality and sexual escapades.  Similarly, tolerance of gays is increasingly less of an issue as well with younger male soldiers as well.  Many join today having had an openly gay classmate in high school, something that even in the early to mid-90's when I was in high school was not common.  I attribute some of this to the prevalence of these topics in media (Sex and the City, etc.) and to a lesser degree, internet pornography that many have grown up with.
If I had to put a demographic to intolerance of gays in the Army, it would be the inner city black males and caucasian males who grew up in small town America.  Both tend to serve in combat arms specialties where "masculinity" is still king and the barrier to entry is lower than other skillsets, not that all who are in combat arms are of lower intelligence.  They are similarly intolerant of females serving as well, as I've experienced first hand when female MPs attempt to apprehend, detain, or discipline such soldiers.  I've taken pleasure each time in encouraging the female to exert her authority and backing her up the whole way.
Given an openly gay soldier in my charge, they would be subject to the same terms of work ethic, teamwork, and integrity as anyone else.  Just like the female soldiers in the MP ranks, they would have to prove their worth by pulling their weight, much like the male soldiers do when they first arrive as Privates.  I've had female soldiers take a piss next to a HMMWV tire in the open when no other option existed as part of the "team".  I've seen males who were afraid to do the same for fear that someone would see them.  Its about differences and respecting them that makes a team, little else matters.
Finally, overturning this policy can't come soon enough as far as I'm concerned.  Too many great Americans have been ridiculed and discharged for no good reason.  I have no doubt that in time this will no longer be an "issue" just as gender integration and race relations have fallen by the wayside.  Similarly, I would like to see females able to serve in direct combat roles, many already have performed the task admirably and received the same awards for their combat action as males.  Nearly all have been Military Police soldiers blazing the trail.  Many of you will disagree with me based on superficial fears or concerns that you've never truly lived with.  I've lived it and I can tell you, its not as big a problem as you might think with today's soldiers  It's the "old guard" that will push back the most and they're close to retirement anyway.