I'm in search of a new router and one thing I would like from it is for the power supply to not generate so much heat as to be almost too hot to touch. That seems like a real waste. I realise that these things are built down to a price, but do any manufacturers use better power supplies? I'm looking at basic Linksys and D-Link routers. My old one that is dying was a ZyXEL.

These power supplies annoy me in general. I have to run several for things like my cable model, speakers etc. I do turn them all off at the end of the day, so at least they are not running 24/7.

Any thoughts?

My Buffalo WHR-HP-G54 has one of those quasi-wall warts where a cord runs from the wall outlet to the transformer, from which it can be removed, and then another, different wire runs into the router from there. It's pretty small and stays just noticeably warm when plugged in 24/7. I also love the router.

The technology is there to build efficient "wall warts". Look at your typical cell-phone charger these days, they don't get warm at all when left plugged in and don't even register on my Kill-a-watt.

I would love to be able to get rid of the half-dozen or so inefficient wall warts I have for my things like speakers, routers, battery chargers, etc.

My Draytek Vigor router uses 4w when on, 5w when making a VOIP call from it and 0w when switch off.

Swapping one wall wart for another is pretty easy - just make sure the replacement has the same
- plug size
- plug polarity
- output type (AC or DC)
- voltage
- wattage (it's OK to have more wattage than the one you're replacing)

"Switching type" wall warts tend to be more efficient, although they're seldom marked as such. One way to get an idea is to plug a 'wart into a kill-a-watt with no load - it should register zero. Another way is simply the weight (switching 'warts tend to be a lot lighter for the same wattage).

There are three variables in plug size:
- inner diameter
- outer diameter
- depth

The easiest way to get a match is to head down to your local radio shack - they usually have an assortment of "dummy plugs" (look for a hanging keyring-like-thing near where their replacement warts and plugs are sold). Yes, RS personnel can sometimes be offensive in their urge to sell you as much as they can. Remember that they are salespeople not techies, so often very basic technical questions can drive them to the other end of the store (or as I like to joke about their slogan : "You have questions - we have deer-in-the-headlights"). Ask enough questions and they will sidle away when you come into the store (stuff like "are these resistors 5% or 10%?").
Anyway, bring the piece of gear the wart is going to be plugged into with you and try all the plugs until you find a fit. That'll be marked outer dia/inner dia/depth. Write that down.
Then (via the web) head over to some surplus electronics places - like American Science and Surplus - or try a froogle search for "AC adapter". It does take a bit of looking.
Note that if the piece of gear you're going to run is 12VDC or 5VDC and only needs to be on when your PC is on (and can be located near your PC) you can just run it from your PC's power (you do have high-efficiency PC PSs, right?). There are power pass-through brackets (I got mine at NexFan.com - but they're obscurely-enough listed that I can't find 'em now).

Finally - audio amplifiers do tend to work better with the old non-switching power supplies. The new "Super T" amps seem to be OK with switchers, but otherwise I wouldn't make this swap for an amp.

Hoping some of this helps...

Very intriguing, I had never thought of doing this. I have a 24/7 server running right next to my modem/gateway/router/wireless, a Vonage VOIP router, and a cordless phone... I'm now investigating the idea of all three "riding" on my server's high-efficiency power supply.

You mean something like this or this? You'd still need to make/buy an adapter cable that had the right interface for your external device, though. Probably the best way would be to snip of the cord of your existing wall wart and use that as a starting point.

I have the D-Link DGS2208 switch and the wart seems very efficient as is the switch itself. With ports unloaded the device takes less than 1 Watt. I would assume their "Green Ethernet" routers are the same although I haven't specifically tested one.

http://www.dlink.com/corporate/environment/dlink-green-ethernet/

Yep.
The easiest way to make an adapter cable is to get some molex "shells" and some "pins". The pins crimp on the conductors of your wire, then push into the shell.
The cheapest way to get barrel connectors (particularly unusual sizes) is to find a cheap 'wart that has the barrel you need and snip.
While you're at this, look at the different barrel connectors for the equipment you've got. Are there any that are the same size but need to be supplying different voltage? You might want to tag the connectors and matching equipment. I used dots of nail polish (borrowed from teenager next-door).