The thing that is most telling is that I haven't changed my installed operating system in 6 months.
Right from the first boot (half the time taken to book Windows XP) it was obvious that Windows 7 was a different prospect to it's predecessors. It is well thought out, robust, friendly, not a resource drain (despite a number of posts and articles recently trying to imply the opposite). Simple things like the integrated device driver database now mean you can plug in any common USB device - that printer in clients office that you have never used before - and be able to use it straight away, no drivers to download, no reboot required.
Windows 7 has worked so well that I am comfortably sat in my office writing this post with my AAO plugged into an external mouse, keyboard and monitor and having a very comfortable and productive experience. These peripherals aren't essentials either - my AAO has been a more-or-less constant companion since I bought it and I would estimate it gets 12+ hours use just about every day.
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I've made only one hardware change to the netbook - I've swapped it's 1GB standard RAM module for the maximum 2GB, but that's it.
Will I need a more powerful computer? Yes - I'll undoubtedly need a more powerful desktop for animation rendering and larger scale 3D work, and I have an old desktop configured as a server, backup and printer host. Will I trade my netbook up for a laptop? Not in the near future. My AAO has served me flawlessly through buiness presentations and anything I have needed to do whilst out on business and it's 6 hour battery life has been a great help. All from a computer that a grand total of about £300. The extreme portability coupled with enough power and the broad features and stability makes this a winning solution for my needs.