Ask HN: How to keep my data, apps, config movable between computers

I want to be able to move my setup (data, apps, config) as effortlessly as possible between physical hardware.

For example, I want to be able to move from a broken machine to a new one without disruption (reinstalling, reconfiguring, moving data).

Do you have a setup or solution to achieve this sort of freedom from hardware (and OS to some extent).

How easy is it to have a linux/windows/(os x) install that can flexibly run on completely different hardware (different graphics cards, networking, etc.)?

Ideas:

- Use a VM player to run everything and back up the image so that for any new machine the only thing to install is the VM player.

- Boot from USB: Limited size/speed/writes. External HD: limited portability. Both: Can OS handle different hardware components on changing "host" machines?

- Avoid platform lock-in. Use cross-platform applications (e.g. Thunderbird) that allow switching OS if necessary.

Is anyone doing something like this? What's your setup/solution?

PS: Background - I'm looking to buy a new laptop and I don't find one for my budget that I like, so I'd go for the cheapest one now and migrate when a better option that I really like comes along. I don't want to reinstall/configure everything every time I move computers.