Are you doing a survey?
I'm a 38 R.
I would stick with a plain charcoal, plain navy (dark is better than light), and subtle self-pattern charcoal or navy depending on what you prefer (I prefer navy but always end up buying charcoal, go figure). But if on a budget go with what's on sale at the outlet even if it's a little more adventurous (e.g. SUBTLE navy pinstripe). It's safe and many argue, the most elegant there is (beauty in restraint, etc.).
In some professions and countries (not sure if Australia is the case), deviating might get you sent home to change, particularly if it's really visible - a light windowpane that's invisible past half a meter might just pass the accountant test, but not a bold light purple ropestripe. A navy suit with crisp white shirt with or without tie will look really neat and professional in virtually every case which is why it's the uniform of choice of almost all politicians (most recently, see photos of Sadiq Khan, the new London Mayor). Single breasted with notch lapels of course (the Tom Ford look in Suits is too bold) and personally I prefer 2 buttons.
The optimal recommended number of suits is 5-10 but no fresh graduate I know could afford that many (I couldn't). Two will get you a long way, three if you can afford it. Don't forget you'll pay a few dollars to get them altered - nothing drastic like changing the shape of the shoulder but definitely take in the waist ($40?), and fit the trousers so they have a light or no break ($15 at the MJ Bale outlet in the Western Suburbs in Sydney) - this because a heavy break means more trouser hanging at the back of your shoe picking up dirt, getting stepped on if you wear thin heels, etc (if it's cold wear thicker socks). The fit is by far the most important thing.
This is pretty much the standard advice on all the threads/books/articles, I read it when I was an undergraduate, ignored it and ended up with a bunch of suits I couldn't really wear after graduation (although they were great for dinner as a student). There's a beautiful DB POW check with light blue windowpane which I miss particularly, but I must have worn it three times.
Also, get at least two pairs of pants with each suit. Even the nice heavy fabrics wear away quickly, and you'll find whatever colour you bought doesn't exist anywhere anymore (it's never quite the same charcoal/navy). You can either rotate, or keep the "nice" one for days where you need to look neat; the problem with the second strategy is that your jacket will age faster than the "kept aside" pants and might end up a subtly different colour. Nobody will really care but it can be really stressful* if you're fashion conscious.
On fabrics, the Instagram lot and many of the classic dressers love birdseye but I've found it has a nasty tendency to snag on stuff at which point you have a few strings of white or contrast light colour poking out of the suit, making it look decidedly worn (and no, the "English Country House look" is not appropriate for a professional services graduate - these stylistic statements are for men who are already established). It also loves to crease incredibly fast and it's a bit of a sportier look (less formal). A sharkskin or herringbone will last longer looking neat.
* Want stressful? try thinking about whether you're showing the same amount of shirt cuff on both sides.
Legend mate! Thank you.
Almost a decade late to jump on the horrible (IMO) diorhomme's mid 2000s treng, might work on the very lank and skinny person but definitely a ridiculous cuit for mass market (probably not the best quality either).