The supreme court case
  US vs Jones (2012) seems relevant.

Justice Alito wrote with respect to privacy: "Short-term monitoring of a person's movements on public streets accords with expectations of privacy" but "the use of longer term GPS monitoring in investigations of most offenses impinges on expectations of privacy"

Prediction for 2019 (made in 1999):

"Most roads now have automated driving systems - networks of monitoring and communication devices that allow computer-controlled automobiles to safely navigate"
  wikipedia

.. but only in binary.

Are you really looking for environment separation? Or is it performance that's the concern?
i.e. You talk about "... a lot of services running, long build times, and so on. To wit, I wouldn't be able to use my desktop for my other purposes like the music editing".

So, if what you are trying to ask is: "how can I do two resource-intensive tasks (e.g. music editing/photoshop + development builds) at the same time without affecting each other on the same box?"

The answer is: you can't. Running virtual machines won't help you. In fact, it will make it worse. Creating virtual machines, or new user accounts doesn't add anymore 'horsepower' to your computer - it just helps you slice up what you already have. The only option is either live with the slowness, or buy new hardware.

If, however, what you want is truly 'environment isolation', then yes, virtual machines could help you.
i.e. the other users of the computer have private financial information stored on the computer, and you are worried that installing IIS will accidentally make it available to the universe
-or-
you think you are going to be installing / uninstalling a lot of software, monkeying with what services are running, etc. as part of your development, and you don't want that to screw up other folks' software ... then yes, a virtual machine will provide complete isolation, at the cost of some performance. It will help if you have a 64-bit OS, and a lot of memory (more than 4 GB).

At some point, you could consider using a 'hosted' machine, like Amazon's upcoming 'workspaces' offering ( http://aws.amazon.com/workspaces/ ) but it's only in beta right now.

Consider that you can be a new desktop/laptop for $200-$300 ..

Crashplan also has a seeding service, where you put your data on a physical hard drive and mail it to them.
http://support.crashplan.com/doku.php/feature/seed_service

Additionally, you can do the same thing with a friend.
http://support.crashplan.com/doku.php/feature/multi_destination_backup

i.e. Take an external hard drive, plug it into your computer, run an initial backup.
Then give it to a friend. You can push incremental backups to them over the internet.
All of your files are fully encrypted, so they can't see them.

I haven't tried either of these features myself (I only use the online service), but I like having the option...

Category and Date.
Overall, I like date-based folders (2010, 2009, etc.).
But first, I use a couple of high-level categories based on the type.

MyFiles
...2010
......ProjectA

MyMedia
...Pics
......2010
...Music
......Artist A

MyFinance
...2010
......BankA

MyFiles
...2010
......ProjectB

Bucket
...random files...

The categories are:

MyMedia / pics -> large files, changes slowly, not replaceable if lost. #1 backup priority
MyFinance -> bank statements, etc. -> small files, old stuff not replaceable, new stuff replaceable . #2 backup priority
MyFiles -> stuff I create / want to keep. -> small files, not replaceable. #3 backup priority
MyMedia / music -> large files, changes slowly, replaceable for $ or time. #4 backup priority
Bucket -> temporary files, downloads, etc. -> mix of large and small files. Not backed up.

This helps me organize my backups.
Nightly backup job copies everything to internal hard disk #2, and an offsite backup (crashplan) backs up offsite categories 1-3.

I don't tag. There's no universal format, so I stick with directories and filenames only.

Quote:
"median earnings for an
advanced degree were 31 percent
higher than earnings for a bachelors degree" - US Census report

High school or more : $26,894 / yr
Some college or more: $32,874 / yr
Bachelor's or more : $46,805 / yr
Advanced degree : $61,287 / yr

Also, looking at the overall education level of the US:

High school or more : 84%
Some college or more: 54%
Bachelor's or more : 27%
Advanced degree : 10%

So, do you want to be part of the 10% group, or the 27% group?

Reference:
http://www.census.gov/prod/2009pubs/p20-560.pdf
"Educational Attainment in the United States: 2007", pg 10

Yes, I know that this doesn't differentiate between master's and PHD, but I think the point is still valid : advanced degrees earn more.

I received my masters in 1995, and I'm very happy that I did. It gives me an extra certification that I'll have for the rest of my life - it helps provide a differentiator in the marketplace, and at many companies, your education level goes into a formula that determines pay raises and salary caps.

So it doesn't just come into play at the salary cap - it can definitely affect your annual raises.

Is it a magic bullet - no. But it sure doesn't hurt.

I also completely agree that a PhD doesn't make sense if you are primarily interested in maximizing your earnings.

And remember, you will NEVER have an easier time getting a masters than right now.

- you are already in 'academic' mode from your undergrad
- you are used to having no money and living like a student
- you don't have the the larger cost basis of modern life (car, house, kids)

While yes, it is possible to go back to school and get a masters later, it is 100 times harder.
You either need to find an employer that will sponsor you + work double hours (work + school), or you have to self-sponsor.

If you self-sponsor and take a year off work to get your masters, you are losing a year of salary + tuition + books + living expenses = $100k + easy.

That gets _reeeeaaallly_ hard to justify.