What are some "good practice" habits and activities which help a
person feel better and have more energy?

For instance, some well known ones are "drink 64 ounces of water per
day", and "exercise 30 minutes per day".

Personally I would say walk a couple of miles a day, walking is an aid
to digestion, a couple of miles minimum is good to get the heart and
lungs working properly and clear the head. 4-5 miles a day in one go
is my ideal, but takes upwards of an hour, and only if its on the way
to assignment do I have the time to do this. Also as a rule its better
to do it in the morning when refreshed and when you don't have the
added tiredness of a hard day at work to deplete your willingness to
try

wolvies

Early to bed and early to rise ... and don't forget to eat an apple a day.

Scriptor

It is very important to get enough sleep. Many sources suggest that
you try to get at least seven hours' sleep per night.

10 Tips to healthy eating and physical activity for you.
http://www.fitness.gov/10tips.html

These are great suggestions!  I'm already thinking of ways I can
implement them into my lifestyle.

For instance, as a web developer, I sit in front of a computer all
day.  Two problems: I have trouble concentrating for 8 hours straight,
and I don't do enough walking/exercise.  Possible solution: Take a 10
minute walk once an hour.  This would work for me because I'd get more
work done in the long run, I'd get some exercise, I'm an independent
contractor (so I can get away with it), and I live in a temperate
climate where I could do this year round.  Might even get a tan if I
combine this technique with wearing a tan-through t-shirt!

Keep them coming! =)

I sit in front of a computer all day, too. My posture is terrible, and
my breathing patterns are probably not very healthful. One thing that
I find refreshing is to take a few deep, slow breaths from time to
time. I tend to have a habit of breathing rather rapidly and
shallowly; several deep breaths make a big difference.

Ohhh... I like this question!  Get yourself an exercise ball.  Use it
for your chair when you sit for long hours at your desk. (Of course
you can use it for exercise too!
 
http://www.fitter1.com/ball_chair.html

I have recently, well a few months ago, started drinking loads and
loads of water daily. I used to be a cola addict but have managed to
wean myself down to just one a day and the rest of the time bottles
and bottles of water. I can really feel the change in me already. My
skin is much clearer and I have tons more energy....

This is a little extreme, but I've heard of people that take a two
minute shower in ice cold water every morning and they swear by it. 
Also eating some protein in the morning can really make a difference,
as well as cutting out caffeine, that will causes you to crash as the
day goes on.

While researching the cold shower suggestion, I ran across this link. 
It has some good ideas:
http://www.askmen.com/fashion/how_to_60/76_how_to.html

Practice Tai Chi everyday to kick the doctor away
http://learn.authentictaichi.com/

or...

Sit on Magnetic Ultra Long Wave chair once a day to energize your body
magnetic field.
http://www.ultralongwave.com/

This is a great question as it applies to so many of us who are
chained to our computers. A comment on your idea to take 10 minutes
every hour --

That's exactly what I do. I set a reminder to pop up on my screen on
the hour. It says, "GET UP NOW!". (I have to be firm with myself!). My
rule is that I have to get up and do something that does not involve
sitting down and I am NOT allowed to come back to the computer before
the 10 mins is up. (I set a timer).

I work from home, so I often add "to do" notes to my pop up reminder
-- ideas for things to do while I'm up (I hate exercise just for the
sake of exercise)-- empty the dishwasher, weed the garden, walk to the
mailbox, whatever. One thing I always try to do is step outside and
"stretch" my eyes .. look far off into the distance. This is important
since it's often your eyes that get tired and make you feel sleepy.

My other rule for myself is that I'm not allowed to eat my meals at my
computer. Consider lunch a time to move .. even if it's just to
another room or a different chair.

That and yes, drinking water continuously, do make a difference in how
I feel. My neck hurts less, my eyes don't get that zoned out sleepy
feeling, and, as an added bonus, my dishwasher gets emptied daily. :-)

Here's the pop up reminder program I use. It's freeware and works like a charm.

Stickies 4.5b
http://www.btinternet.com/~tom.revell/
 
-K~