Meeting clients first time I am in smart jeans and causal shirt with comfortable shoes. The last time I checked they are wanting to hire me for my technical ability not my catwalk ability.
However, I try to set the dress code tone by meeting in places like Starbucks or Costa coffee.. Have I lost work because of my dress? Not to my knowledge, but if someone has not given me the work because of my smart jeans and shirt, then maybe they are not client for me. This dress applies to when I'm visit their site/office location
I cannot recall anyone all the time I have been doing that anyone complained about my dress code...I think this has a lot to do with as my client base as majority are small (1 to 50 employees) business.
There are lot of companies still out there like someone said politics, financial, law sectors that are very traditional, but probably need to get with times and loose up the tie once in a while..