Hey mates.
I will be doing a few overnighters with the wife this year, then an end goal of doing the overland track in Tassie later this year.
My main question at this time is the type of bag I should be looking at. More importantly, the size.
This is the one I have lined up, but it comes in a 50L and a 65L.
http://www.paddypallin.com.au/osprey-atmos-65-anti-gravitytm-pack-mens.html
The packs I’ve found to be the most comfortable and very rugged are made by One Planet and Wilderness Equipment. Lauren has a One Planet Mungo and I have a WE Breakout. I got mine for $50 on Gumtree and it’s really great. Very basic, but very tough and comfortable. One Planet packs are still made in Aussie too, pretty much the only ones that are. It’s really truly worth trying on any pack you’re interested in, with a load in them. 50 - 65L sounds about right for the Overland. Maybe closer to 65l than 50L though, depending on the rest of your gear.
Summit gear still make packs in Sydney and Katoomba, and they seem a bit cheaper than one planet… more classicly boxy, often zero zippers, ultra rugged. One planet looks superbly comfy though. Ezy, these listed packs are all tough as nails, and 20 years is not an unsually long time to be using them for. I still have my macpac torre from 1999 and there’s hardly a scratch on it, still carries 20kg+ comfortably, and I can happily push through scrub knowing nothing will catch and tear on it. I’d look away from the osprey packs and go for the Aus/NZ style of hardy canvas for this reason. I have a few you can try on, around that size you’re looking at. And Kristen has an old macpac that V could test too.
I know that might sound hard-nosed and anti-tech, but my sample of one osprey was not tough.
Like Pete’s experience, second had is great… Especially wilderness equipment and macpac, as i reckon their newer stuff isnt quite as great.
ftfy
Cuben fiber or don’t even bother.
If your doing on track walking in Aus I think a lighter “modern” xpac/cordua bag is fine.
Off track and more remote stuff or your doing it ALOT then a more rugged pack is better.
and yes I’d go for 65lt, 50lt will be a little small for the overland I have an 80lt macpac Torre pack and its huge and very tough (used it for work in the bush) but recently bought a much lighter and for me more comfortabe Exped 65l pack.
The other advantage of more modern materials is that they dry out faster which is handy in Tas.
What ever you do make sure the back length/harness is adyustable.
Ding ding, I have one the last made in NZ Torres!
and finally make sure you try the pack on with ~12-15kgs in it before you buy.
I tried on 5 packs before I bought y exped, one Dueter was terrible, one osprey was very good but another (non adjustable) was also terrible but the higher end osprey was very good but ~$400
The bag is led by the type of load you will carry.
I recommend buying the smallest bag that will do the job, rather than a big one that you might fill. This is the one on my wishlist: http://www.bogong.com.au/exped-lightning-45-pack-1.html
I’d suggest making a list of your gear (both what you have and what you plan on getting) at https://www.lighterpack.com/
Here is my in=progress list for bikepacking - note that it doesn’t have anything for cooking, as this is my eat-in-town list: https://www.lighterpack.com/r/33481m
Here is a list from someone on Reddit Ultralight who is planning on doing the Pacific Crest Trail in the US: https://lighterpack.com/r/6766on
An option that you might consider is hiring gear to give it a trial without committing. I don’t know of any hire places in Canberra to recommend, but if you do anything near Melb, Bogong are awesome: http://www.bogong.com.au/hire
I have One Planet packs too. Really great. Recommend 65lt also.
Thank you to everyone for your input.
My wife already has an Osprey pack which she used when she took her school kids over to Borneo. It held up quite well in the humidity and bush that she hiked 6 nights through.
To be honest, I don’t imagine we will be bush bashing at this stage so the more rugged bags might be a bit overkill.
Don’t worry, the luggage handlers at the airport will give your pack more of a bashing than any bush track will.
My wife has a One Planet pack she might be willing to sell. It’s in excellent condition. Let me know if you’re interested.
Depends on the colour
Browsing the Ultralight subreddit takes up a large portion of my work day 
Agree with everyone who says to try a bunch of packs on and prioritise the fit. Walking with a sore back is pretty miserable.
I’ll vouch for the One Planets too. We love ours. Definitely one of the pricier options though.
Size probably depends on your other gear and how you like to hike/camp. We would struggle with 50L but my wife feels the cold so she has a big-ish sleeping bag and puffy jacket in her pack all the time, and we like camp cooking so usually haul a fair bit of not-so-space-efficient food (plus, ya know, coffee). We could definitely pack less but then we wouldn’t enjoy the trip as much.
On the other hand, hauling a backpack that’s too heavy for you also sucks. So if you two aren’t comfortable carrying weight all day then a smaller bag may help save you from yourself re: packing!
Tough packs aren’t that much of a compromise I reckon
Zing
This is the thing bough - which is what attracted me to Osprey…
“Osprey will repair any damage or defect for any reason free of charge – whether it was purchased in 1974 or yesterday. If we are unable to perform a functional repair on your pack, we will happily replace it. We proudly stand behind this guarantee, so much so that it bears the signature of company founder and head designer, Mike Pfotenhauer.”
A lifetime repair guarantee is all well and good, but if you’re in the middle of nowhere and your pack falls apart- you’re fucked.
It’s the equivalent of a Knog warranty.
“We know we make shit products that have significant design flaws. We know they will fail at the most inconvenient moment. We make enough money on the markup, and realise not everyone is going to ask for a replacement, so the few we do give out are incorporated into our overhead. Here, have a free replacement, have you seen our latest Kickstarter?”