I'm on the tacky train with Maya, Kristen, and the rest. I think tacky actually does have a clear meaning, and think it works in certain situations. I agree with Marianne about tacky vs. cheap, and I much prefer tacky, because anyone can be tacky, including the wealthiest person in the world. Cheap, on the other hand, has more of a classist connotation, and to me seems less clear because it has multiple meanings. Also, I don't like it when the word cheap is used to mean a word like tacky or tawdry ("yuck, she looks so cheap in that outfit"), because it implies that anything that is cheap (aka inexpensive) is bad.
I probably didn't explain that well, so I'll make an analogy. When I was growing up, it was accepted to use the word "gay" to mean stupid, ridiculous, etc. As in "Hootie and the Blowfish are so gay." I never thought anything of it until someone who was gay said to me that it was damaging because using gay in that way extended the connotation to gay people. Now you never hear people use the word gay like that. I think cheap is similar.
But I think Angie was saying her hatred of the word tacky was irrational, right? That it's just one of those words she doesn't like the sound of? (For me, that word is mucus.)