That said, here are some comments on why terms do or do not bother me:
Sexual Preference - I don't mind this one at all if it is used for what it means. People do have preferences for specific sex acts, or specific circumstances of having sex and so forth. I think anyone could write a whole essay on his or her sexual preferences (and, actually, I'd love to read them if anybody on my friends list wants to write one, because I'm prurient that way). But I hate it when it's used in a context where it's meant to refer to being gay or lesbian. It trivializes our lives and denies the reality of sexual orientation and sexual identity. And it's never used for heterosexuals, just to set us apart.
Gay, as a noun - I can't really say why this happened, but it seems to me that somewhere around the mid-1970s this usage went from a general one to the exclusive province of homophobes. People say "I am gay" or even, in McGreevey's case, "I am a gay American" but nobody says "I'm a gay" and if someone says "gays and lesbians" instead of "gay men and lesbians" it's a bit of a tip off. Now, obviously someone could say "gays and lesbians" just because s/he doesn't know who uses it, but in general I find it is not a good sign when this term is used.
"Lifestyle" bothers me much like "sexual preference." It trivializes our lives. Straight people have lives but we just have lifestyles. Blecch!
I resisted "queer" for a long time. At one of the first organizing meetings of Queer Nation someone stood up and said "Why do you want to use that word? That's the word they use when they're beating us senseless!" I cheered that guy. I didn't want to reclaim it - I think, like pink triangles, it's a symbol of our oppression, not our pride. But I've given in. Partly because it's just so ubiquitous now, and partly because it's so useful. We really need a general term that covers gay, lesbian, bisexual and transgendered and isn't an unpronounceable collection of initials.
"Dyke" and "Fag" are terms that are fine to me when used by dykes and fags, but I find them suspect when used by others.
I think "gay marriage" both trivializes our marriages (they're not marriages, just "gay marriages") and is inaccurate.
I think "homosex" is just fine, which is where I came in on this one. I use it, I hear it used, my characters use it; I think it wholly unremarkable and a useful term to cover a variety of same-sex sexual activity. I do think it's often used ironically, but I don't mind when it's not.
Terms for a Member of a Committed Same-Sex Couple
Lover - I find this one pretty contextual. In straight society, lover means "sex partner" or even "illicit sex partner" but in gay and lesbian circles it has long meant that one is a member of a social couple. Tom Hanks showed his understanding of that when he thanked his lover (meaning his wife) when he accepted the Oscar for his role in Philadelphia. It's starting to sound a little old-fashioned, I think, as other terms have been taking over, but in queer circles I think it's always understood as meaning something more than a trick.
I hate "roommate" and "friend." I can't think of a good context to use those when referring to a committed partner. People use it about their own partners when afraid to come out and people use it about others' partners when not wanting to acknowledge the true nature of the relationship.
I seem to be the only one bugged by girlfriend/boyfriend but I feel it trivializes committed relationships (making them seem less than straight marriages and more like the precursors to straight marriages) when used for such. And even for relationships not at that level of commitment (e.g. dating relationships) I feel that for those of us well past boyhood or girlhood it's infantilizing. "Girlfriend" in particular also is potentially confusing - it can mean "female friend". I was at my lover's union's annual picnic a couple of weeks ago and she said "Come on - I want to introduce you to the president of our local." I said, "Fine, but don't call me your girlfriend."
"Significant Other" and "Partner" are okay with me, but I'm not thrilled with either. The first just feels so coined and the second is often subject to confusion, particularly if one has a business partner. My friend Leah once said "I wish partner didn't sound so business-y and lover didn't sound so bedroom-y." But I do think "partner" has become kind of the default term used by accepting straight people.
I used "spouse" when I was married. I thought it made things really clear. People did assume my spouse was a man, but I corrected them right away and underlined the point I was trying to make in the process: our relationship is just as valid as theirs, even though we don't have equal rights.
I do find "husband" and "wife" grate a little to me still. They feel too gendered to my ears. But I believe in calling people what they want to be called and use the terms in referring to people who prefer them (e.g. my sister and the woman she is married to refer to each other as "wife"). I think over time I'll get comfortable with them.
I'll end by echoing marag's comment that any term rubs me the wrong way when clearly being used as a slur.