Wireless phone for my land line

Okay, so it's a cordless phone for my land line, not a wireless phone ;)

I've been looking for the ideal cordless phone. This has really turned out to be a challenge.

My requirements were simple:
- It must have an answering machine
- must support multiple handsets
- should not interfere with my home wireless network.

The solution to last point would appear to be a no-brainer - just get a 5.8Ghz phone, since wireless networks run at 2.4Ghz - right? Well, an number of so-called 5.8Ghz phones also run at 2.4GHz. To quote an excerpt from the owner's manual for the AT&T E5865 5.8 GHz Cordless Speakerphone/Answering System:

"RF Frequency Band (Handset to Base) - 2400 MHz ? 2483.5 MHz
RF Frequency Band (Base to Handset) - 5725 MHz ? 5850 MHz"

Um, why do I see 2.4GHz there? I must confess that I would not have picked this up if it wasn't for the excellent Consumer Reports magazine and website.
To quote from Consumer Reports "Cordless phones: Sound distinctions" dated October 2004:
"Some phones are dual-band, which means they transmit between base and handset in one band and receive in another. You can't switch the frequencies. One of those bands might cause an interference problem"

One of the true 5.8GHz phones I came across was the Uniden TRU 8885-2. The only problem with this combo is that it does not have a battery backup. A newer model, the Uniden CLX485, does have battery backup, but is a lot more expensive, and - as yet - unproven.

Cordless phones also seem to be getting closer to cellphones with features like:
- downloadable ringtones
- picture caller id (in color!)
- synchronize phonebook (yes, they have phonebooks!) with Outlook
- handset-to-handset talk
- lighted keypad
- multilingual menus

Other resources which proved useful during my research were:

CNET Product Reviews and the websites of stores like Circuit City, both of which have customer reviews. Manufacturer websites like AT&T and Panasonic are wonderful places where you can download owner's manuals.