I have room for one more accessory, I already have an optical drive, card reader, LCD panel (for showing temps and system stats) and fan controller. Between those and the audio and USB ports on the front of my case I can't think of anything else to stick in there, but that blank bay is bugging me.

Hard drive devices aren't necessary since I use network backups and silenced 2.5" drives in the internal bays.

PS: If anyone knows a 5.25 to 3.5 adapter with any extra features I'd really like to get one. The Fatal1ty audio panel doesn't count.

How about a useful cigarette lighter/beverage tray?

http://www.amazon.com/Thermaltake-A2021 ... B0002F8WLM

As one of the customer reviews says:

"Can you imagine! Being able to drink coffee and smoke at your computer without having to look for a lighter or a place to set your cup. What will they think of next?"

Interesting, but I sit too far from the tower for that to be practical.

Out of curiosity, I once tried to see what could be mounted in a drive tray.

In addition to the devices already mentioned, I found:

A mobile rack for swapping disk drives.

A drawer to store small items.

Stereo speakers.

A stereo amplifier.

An infrared sensor for a remote control.

A drive bay mounted UPS to power the computer.

An air conditioner.

And strangest of all, a Toaster!

Scythe KC01 - PBK - 5 "Kama Cabinet" a drawer in a 5.25" bay
http://www.newegg.com/Product/Product.a ... 6811998076

I haven't seen it, but what I thought somebody should devise is a drive bay
charger/dock for PDAs, MP3 players, etc. (maybe compact cameras)

i.e. one provide socket to insert the device(s) where they could be stored (out of dust), charged, and be connected to the computer.
Each device might have its own fitted socket that it would slide into and mate with a connector. More generic would be a drawer with charging/connection cables in it (but that would be a bit of a bother finding the right cable and hooking it up).

Other ideas:
How about that Zalman power use meter that was recently reviewed here.

Wire up a microcontroller, some LEDs and make a blinkinglights panel http://en.wikipedia.org/wiki/Blinkenlights (Use multi-colored LEDs for that festive holiday look).

Put in an LED text display panel (set up as a ticker for SPCR forum posts
Add a larger or second LCD or OLED panel (http://www.lcdgallery.net/) - you can never have too much bling.

A clock (of whatever persuasion you want - hack a day has all sorts of clock display ideas).

Would be okay place to mount a fingerprint reader or a magnetic stripe card reader.
Come to think of it, if you have some open space inside the computer around it you might even be able to shoehorn a label printer in there.

I put one of these in a recent build:
http://www.welland.com.tw/html/mobile/220.html
Useful for backups etc.

http://www.newegg.com/Product/Product.a ... -_-Product

Not for low power fans, but plenty of bling.

http://www.newegg.com/Product/Product.a ... 6811992004

This one may be green, you won't need any other lights on in the room.

http://www.svc.com/tr-5b.html

As with the others, this one is best described as, "OW! My eyes!"