This is a nice datasheet, good looks.
I might add in a little extra around the CBD (downtown) areas specifically as I live there and it's my main going out area Thursday - Saturday, as the OP mentioned if you are wanting to head out Monday - Wednesday you'd be better off with the backpacker spots, I don't do these however as I'm too old.
Warm up spots (6-9pm):
Ryan's Bar: on George St, basically a massive outdoor courtyard bar, very busy from 5pm onwards on Fridays, clears out by 9ish as people go home or head out to proper spots but not bad for swooping some early digits
Del Medio: on york St, Cuban bar, cocktails and a few beers, again busy from 6 til 9ish, has a basement with a band, often groups of more 'corporate' type after work chicks, not really my bag but a nice midweek date spot also, apply online for a free memebership and get $10 mojitos...
Baxters: Clarence Street
Fairly new basement 'Whiskey' bar, basically a wall of rare whiskies, rockabilly music and a 50's vibe. Was painfully hipster a few months ago but now becoming mainstrream, still normally a line and elbow to elbow at weekends. Inconsistent quality of chicks but normally a few OK ones.
Stitch:
York Street, looks like a tailors shop from outside, descend the stairs and its a pretty cool cocktail bar, more of a group hangout spot and a nice, quiet midweek date joint.
CBD Hotel: York St
Standard pub with a DJ, very busy earlier on Fridays, quite a few chicks normally
Sanctuary Hotel: Sussex Street
Big hotel with an outdoor space at the front where you can grab a jug and check out the street action around. This is basically an Asian joint with a few tourists mixed in
Prime time spots (8pm onwards)
Establishment: George Street
Once the go to spot in Sydney, overshadowed by some newer joints now but still very popular. Nice decor and space, looks classier than it feels when you're there... nicknamed 'The Drycleaners' (pick up a suit). This is defenitly an older (plus 30) after work crowd for the most part though a few younger honeys there as well sometimes. In my opinion very courgar-ish and often the ratio is piss poor but worth a look, or go upstarirs to...
Hemmesphere: George Street
Cocktail bar above Establishment, more expensive, table service, some nice looking chicks in groups but kind of hard to open here for me
Zeta Bar: George Street
Above the hilton hotel, take the lift up. A pretty classy venue, nice outdoor deck for the smokers. Fridays have been pretty quiet recently but still enough potential for a visit. Saturdays are a house night with a decent local DJ and sometimes some well picked internationals, haven't been for a while but usually packed, dressy. nice ho's.
Also below Zeta in the basement there is a pub type bar which has a live funk band on Fridays, is PACKED out every week and full of lower grade chicks, if thats your bag, casual dress.
Arthouse: Pitt St
Huge multi room / level venue that doesn't really hang together and never seems busy these days, sometimes have big saturday night dance events, not overly recommended.
Argyle: The Rocks
As mentioned by the OP, a big, 2 level venue, seems to be constantly having mini 'refits' but is a cool spot with a big outside area, large bar/standing downstairs and a more dancefloor vibe upstairs. Fridays seem to flatten out pretty early, Saturdays are busier and will have cheesey dance upstairs, normally a reasonable ratio, standard OK to Good. Free entry
101 Bar: The Rocks
A stones throw from the Argyle. a pretty new venue that does'nt really work for me. Not overly busy at prime time the couple of times i've checked it but may have picked up now. Nice deck downstairs but other than that standard 'nitespot'. If you like Lebanese girls go here.
333: George St
Also mentioned by OP. Opposite the Ivy. Downstairs standing and drinking, upstairs dancefloor, pretty random crowd in my experience, some hot girls sometimes. OK for a quick look in but why eat burger when there's steak across the street...
The Ivy: George Street
In the interests of disclosure this is my no 1 go to spot week in week out so this may be a little biased.
A stunning venue by any standards, multi level / room, many areas and nooks and crannies, multiple restauraunts and bars within the venue. Up until around 2 years ago this was THE spot to go in Sydney, was hard to get in and the standard was incredibly high. These days, due to competing venues (Marquee) opening up it's pretty easy to get in for the average joe/jane, the dress code has pretty much been abandoned, howoever this is a bonus if you rock suits/blazers/skinny ties etc as you will get checks.
It's still always reliably busy, a good ratio, some fly honeys and HEAPS of asians (both Aussie born and a smorgasbord of Korean/Thai/Jap/Chinese on any given night). Has a very good flow and due to the layout of the venue you can game in mutiple different areas throughout the night.For me this is ultimately one of those spots that 'just works', fun and a party vibe.
Fridays are a mixed after work crowd with a lot of younger people arriving also after 11pm. Saturdays are better music (house, commercial but bearable) but crowd is impossible to call on a week by week basis, shitty one week, teams of asian models the next... go figure. $20 cover after 9pm Friday and Sat.
80% outdoor so can smoke freely
Ivy Pool: George Street
Although part of the same buidling (actually its pretty much a block) this is a seperate venue with separate door pickers, a different entrance and accessed via elevator. Used to be near impossible to get into without a membership, now pretty much no problem as long as you don't look like shit.
The main pool is, well basically a pool bar / cabana type thing, DJ's, older crowd than downstairs, some hot chicks but attitude to match. Much smaller than the main Ivy. Worth a look for novelty value but personally would just hit the main joint, younger chicks and a better selection. Figure on a $20 cover after 9 at weekend but if you're regular, very well dressed or the door whore just got a raise or something you'll slide in free.
80% outdoor so can smoke freely
Sundays they have a day party here in summer, have'nt been but will soon.
Cargo Bar: King Street Wharf
Pretty big, busy weekend venue, younger crowd (20-26), crappy electro music, usually a good amount of girls.
Bungalow 8: King Street Wharf
Much the same as above, classier looking venue in my opinion. Has a seperate bar called Loft upstairs that's harder to get into, smaller but usually hotter chicks and better beats. Also a good date spot.
After Hours spots: (3am onwards)
You have failed in your mission and wish to continue? or you want to bounce with your swoopee for more lubricating drinks?
Spice: Elizabeth Street (Martin place)
Underground dance spot close to all the George St venues and Ivy, go;s through til 11am on weekend, very credible house music policy. This is also a daytime restaurant and cocktail venue hence it looks classy and the drinks are dope. Bouncers also friendly. Usually a bit of a cockfest but some cute, and cool chicks around sometimes, tend to be friendly also. $20ish
121: Pitt St (I think), behind an alley.
Younger crowd than Spice, again, underground house, techno, cetainly possible to pick up a trashed young un here at 5am.
Arq: Taylor Square (Oxford Street)
Cavernous gay club, don't go if you are offended by bare male chests, however, friendly environment, always pockets of girls kicking on and for some reason, often a high ratio of Asian honeys

$25
Colombian: Oxford Street
Ostensibly gay, cool 2 level bar with nice beats (deep house). Usually a decent amount of girls but quality wise a roulette wheel, pretty trashy. free
Goldfish: Kings X
Cool bar / club, kicks off after 3am, always good music and wasted girls
More to come soon...