Forgot to add that in the past, I have always dressed fashionably, but smartly, for every interview I've been to and amazingly(!), I have never not got the job!
TBH, I think if you are dressed well (even if it is a little 'too fashionably'!), can speak intelligently and fluently and are what they are looking for, in every other way, most employers will normally give you the job, anyway.
This is because most of them know that it's always better to employ the best candidate and (if necessary) ask them to tone down their dress, slightly, than it is to employ the less good candidate.
I have always felt that it would be slightly dishonest for me to dress in a conservative suit for an interview, if I never intended to wear one ever again and I, personally, wouldn't want a job if the employer didn't like the real me!
The most conservatively I have ever dressed for an interview, was in a fashionable (at the time) grey suit with a longish mini-skirt (with tights)!
At least every employer has known exactly what they are getting, right from the get-go, when they've employed me!
I'm sure this is a slightly risky strategy, so please proceed with extreme caution if you really want the job, but still!