If I were in the market, I'd get a Chromebook:
http://www.jbhifi.com.au/computers/chromebook/
If you only ever use browser-based apps, a Chromebook could be very good value - especially at less than $400 for the Samsung model.
Just be aware of the limitations - you can only install apps designed for Chrome (which are mostly just online cloud-based apps that you can access from any browser on any device).
You can't even install Android apps - so the only document editing tools you have available are via Google Docs. Not that this is much of a problem if your document creation needs are modest - I run my entire business on cloud based apps, haven't had MS Office installed for years.
What's more, you are entirely tied to Google's ecosystem for backup / synchronisation / data storage / etc. You really don't get a choice.
I was researching this recently and came to the conclusion that, unless budget was your #1 priority and functionality was not as important (in which case you could possibly get away with a Chromebook) ... then an Android-based tablet paired with a good blue-tooth keyboard would be a better option.
A tablet gives you access to the massive library of Android applications - many of which are reasonable substitutes for desktop applications, there's a far larger choice of hardware available, and you get the flexibility of a touch-screen device as well.
My current laptop is reaching the end of its useful life for me, I've been looking at replacing it with a high-end custom-built workstation with support for 4 or more monitors for my day-to-day application development work.
Then for when I need to go mobile, getting a powerful tablet (I have a 2 year old Asus Transformer which is great, but starting to show its age), coupled with a nice bluetooth keyboard - much more compact, and can do pretty much anything I need while on the road, other than serious application development (even then, I can do text editing as required).
With good sync services available now (I use Dropbox + Google Drive + Evernote), plus most of my business systems working out of the cloud, I can use pretty much any device anywhere to do most of my work - the hardware effectively becomes commoditised.
For those situations where I'm not at my office, but really need access to the applications I run on my workstation because the tablet just can't handle them ... there's always remote access! I use Teamviewer, works great on a tablet, can run apps off my main computer from anywhere in the world!
It won't be long and I'll be able to simply move my main workstation to the cloud, and access it remotely from where-ever on what-ever device I happen to be sitting in front of. Commoditised workstation! The thing I sit in front of at my office then effectively becomes not much more than a thin-client giving me input and output from my remote/online workstation.
I've already moved my development server to the cloud - I got sick of fighting my local machine trying to get my software development tools running on it, so I simply set up a new VPS (in Tokyo!) for my Dev server and I access everything remotely. Any time I save a file in my editor, it automatically saves to the VPS via SSH, and I test my applications from there. I can even do remote debugging over the internet.
THIS is why I want an FTTP NBN ... I can do so much more with ubiquitous very high speed internet!