A couple months ago I bought a power consumption meter and I've done a number of measurements.  I was only interested in quantitive amounts, that's why the some descriptions are inexact.  Here they are:

Videoton Precision 2000 - 56 cm diameter CRT TV

• idle: 4W
• powered on, dark screen: 65W
• powered on, bright screen: 85W

noisy (a PC of mine)

• idle, wake on LAN ready: 6W
• powered on, idle CPU: 104W
• powered on, busy CPU: 120W

LG Flatron F700P - 17'' CRT monitor

• idle: 0.4W
• dark screen: 77W
• bright screen: 95W

Videoton Waltham TS 3343 - 53 cm diameter CRT TV

• idle: 1.5W
• blank screen: 50W
• bright screen: 60W

Sony DVP-NS32 - DVD player (you shouldn't buy this piece of sh*t)

• enabled: 7W
• audio cd playing: 9W
• divx playing: 10W

Technics SA-GX130 - stereo synthesizer receiver + 2x big loudspeakers (don't ask how big)

• idle: 1W
• not so loud: 19W
• pretty loud: 40W

Toaster:  725W

Grundig P45-342CTI - 42 cm diameter CRT TV

• idle: 12W
• blank screen: 60W
• bright screen: 80W

My mother's halogen lamp: 26W

Pirelli DISCUS DRG A225G - all-in-one broadband DSL router

• powered on: 7W
• DSL link up: +1W
• active phone call: +1W

ASUS WL-500GPV2 - DSL router

• idle CPU: 2.2W
• busy CPU: ???W

Samsung 204B - TFT monitor

• idle: 0.7W
• powered on: 22W

Water pump that circulates the water for the house heating system: 44W

Goldstar ER-3520D - microwave owen: 830W

ENERGY SAVING TIPS

• Try to avoid to generate heat using electricity because it draws a vast amount of power.
• PCs are power hungry due to their inefficient power supply, so it's better to use laptops.
• Use compact fluorescent lamps instead of incandescent light bulbs.  They are being replaced in the EU anyways.
• You can keep your CRT TVs because in spite LCD TVs are power efficient per-inch wise, they're also larger than CRTs, so they're usually more power hungry in overall.  Plasma TVs are very power hungry on the other hand. LED TVs are the most power efficient, but it'll take some time for their prices to drop.  It's probably worth waiting for them.
• You should absolutely replace your CRT monitors with an LCD.

What do I mean by "mechanics"?  Well, considering that every recent mice use purely light (either optical or laser) for motion tracking, the only mechanics left in mice are microswitches.  These switches are usually provided by OMRON and most of their switches can endure about 10 million operations which may sound much but I guarantee you that it won't last more than several years of intensive usage.  What I want to conclude is that the current design of mice is potentially incredibly durable, except the microswitches.

Given the kind of green person I am and considering how much I hate planned obsolescence, I was thinking on how is it possible to maximize the lifetime of a mouse with minimal resources.  The operations below require a soldering station and a modest amount of soldering skills (or a friend who has the equipment and is willing to do the work for a beer).

1) Switch swap

Switches do not completely die from one moment to another in my experience.  Usually you notice that drag and drop operations are hard to make because the switch cannot operate correctly during sustained action.  Once you think about drag and drop and you realize that only the left mouse button is used for it and others are not used for sustained operations you immediately ask the question: why not swap them?

The middle and right buttons are very rarely used compared to the left button so they can last about 10x (right button) to 100x (middle button) longer.  First, you can swap the left and middle buttons and several years later you can swap the (then) left and right buttons.  This should give you alone a 3x durability for no money!

2) Buying a new switch

Once it gets inevitable you have to buy a new microswitch eventually.  The challenge is that the exact switch model you need is probably not in the market by that time because the manufacturer have obsoleted it.  However, it's probably possible to find another switch with almost identical dimensional and mechanical characteristics, so keep looking!  I'd really love to see a site listing all the microswitches that are on the market for various mouse models.

3) Designing a mice for durability

Even though mouse manufacturers have no financial incentive to design a mouse for a lifetime, it's worthwile to think about the issue.  Putting the microswitches into sockets for easy replaceability and providing replacement switches for sale and/or bundling a dozen of them with the mouse itself would solve the issue.

Enjoy and make your mouse last forever!