Rod Dreher has an enjoyable rant against the worst:
I have a perverse fascination with ugly churches. They're supposed to lift our eyes toward heaven, and to help us connect to God. It is vitally important for churches to be beautiful, no matter what style (and many different styles can be beautiful ... though not all styles are). Given the stakes, when churches fail aesthetically, they fail epically. Consider Our Lady of Chernobyl, in suburban New York, or the Florida church complex that looks like an bologna ziggurat sculpted by Oscar Mayer, next to a giant tortilla warmer. This is what happens when people forget what church architecture and design is for, and when insecure clergy and church lay leadership get fugaboo'd and intimidated by architects who want to make a Statement.