As someone from the fashion world , which is like the so called perfect place for beauty, clothes and size,  I am the least fashionable person but that doesn’t mean I don’t  fit in .
I think how you dress for work is  a very personal choice and yes definitely you make the first impression with how you dress but  honestly it’s not so much about your clothes or your choice of accessories  but how you carry yourself and what’s your distinct style .
I definitely believe in confident dressing , one should wear what suits their personality and conveys who they are , also power dressing is definitely not about brands or the cost of what you wear  , it is about evoking competence , confidence and yes authority too .
Also your dressing should not be a contradiction to the values or the tone you are  setting for your work , I mean you can’t wear a croc leather jacket or alligator leather shoes and talk about saving the the planet or about sustainability .
For me personally power dressing means to be able to own what I wear and at the same time be totally  comfortable in it , to make that little effort to put together an attire as per how I feel that day and what I want to accomplish at work.
So the choice can be a Saree or well designed suit or even  that  casual Jeans and and the perfectly ironed white shirt or blouse , no jewellery , solitaires or chunky jewellery but u just have to rock it and feel amazing.(CONFIDENT , CRISP, CLEAN And COMFORTABLE are my key words ).

Interesting question, Conci ! I have gone the full circle in corporate dressing. Had phases of wearing just western formals then felt it was too ‘just-out-of-B-school’-ish. Wore ethnic Fab India clothes for a long period, then saw everyone around wearing similar stuff and tried to look for alternate styles. After a time of Indian dressing, craved for suits and skirts again.
So, no set rules. Just dress sharp and smart and most importantly, comfortable. Look good to yourself. Have a lot of admiration for SBI ex-Chairman Arundhati Bhattacharya. She joined Salesforce, a Silicon Valley Company, after a lifetime at the Indian behemoth Government-owned bank. And has no qualms about ditching a lifetime of silk and cotton sarees for jeans and shirt! Just check out her recent pics. Don’t hold back from reinventing yourself.

How you dress goes a long way towards how you are perceived in the company, especially during your first few weeks. Its always beneficial to leave a good first impression.
Watch what the senior professionals in your organisation are wearing, are there any patterns. If they all dress a certain way, then it may not be a bad idea to follow similar guidelines.
My first job out of B School was with an old school manufacturing organisation. I was 22 years old in a management role (albeit junior) and people twice my age with way more experience than me, were lower down in the organisation structure and there was a lot of discomfort with the concept of ‘management trainees’ who had been brought in for the first time. I wore a sari everyday to that office and it made people take me more seriously. What I wore, was only a part of the change in attitude towards me, but it did play a significant part in how I was perceived.
My next organisation was in a start up in the IT industry – here things were less formal – we could wear whatever we liked to office – jeans / skirts etc, it did not matter. When I moved to the US with this company, it was formal blouses and skirts or trousers, often with a blazer and casual dressing on Fridays.
The one after that was a well established IT company. Here we tended to wear salwar kameez or Western style semi formals Mon-Thu and casual dressing on Friday.
When I was teaching, it was again saris
Since then I’ve done a lot of free lance work with organisations. It doesn’t matter how casual the organisation policy is, I’m always dressed in semi formals for meetings and saris when delivering training. Minimalistic accessories – because I don’t want them to distract from my work.
I’ve seen start ups and ad agencies where individual quirkiness is encouraged/celebrated and it shows in their dressing too, the key is to watch what works in your particular organisation and take your cues from there. Settle in, let your work speak for you, once you’ve established yourself and your work ethic, go ahead and push boundaries.
I realise that what I’m saying is quite an anti thesis to the ‘be yourself’ philosophy of the moment. But remember that the people who will be making decisions about your career growth are most likely from an older generation. So know your audience and dress for the job you want.