I went looking for a modem to handle a software based answering machine.

Came up with this one:

Multi-Tech MultiModemZDX MT5656ZDX-V
56K Technology V.90, V.92  
Cables Included 1 x phone cable  
Compliant Standards FCC Class B certified, CE  
Connections 1 x serial - RS-232 - 25 pin D-Sub (DB-25)  
Connectivity Technology Wired  
Data Compression Protocol MNP-5, ITU V.42bis, ITU V.44  
Depth 5.7 in  
Device Type Fax / modem  
Enclosure Type External  
Error Correction Protocol ITU V.42  
Fax Compatibility G3  
Features Auto answer  
Height 1 in  
Humidity Range Operating 25 - 85%  
Interface Type Serial RS-232  
Interfaces 1 x modem - phone line - RJ-11 - 2 ¦ 1 x microphone - input - 1 ¦ 1 x speakers - output - 1  
Localization Canada, United States  
Max Fax Transfer Rate 14.4 Kbps  
Max Operating Temperature 122 °F  
Max Transfer Rate 56 Kbps  
Min Operating Temperature 32 °F  
OS Required Microsoft Windows 95, SCO OpenServer, Linux, Microsoft Windows NT, Microsoft Windows XP, Microsoft Windows 98/ME/2000  
Protocols & Specifications ITU V.34, ITU V.90, ITU V.17, ITU V.92 , Hayes AT command set  
Service & Support 10 years warranty  
Service & Support Details Limited warranty - parts and labor - 10 years - carry-in  
Software Included Drivers
Utilities  
Voice Communication Support Voice mail, speakerphone  
Weight 0.4 lbs  
Width 4.3 in  
Weight of Product 1.5 lbs. 
Manufacturer Part Number MT5656ZDX-V  
Web Product Description V.92 VOICE/DATA/FAX MODEM  
Manual: http://www.multitech.com/DOCUMENTS/Collateral/manuals/S000248G.pdf

I'll post more up once it arrives... and how well it works, etc.

Update: Excellent modem.  Drivers were a bit annoying to install, but the product is rock solid.  Excellent fax/data modem with basic voice functionality.  If you're serious about voice, get a USB or dedicated PCI voice card.  This was perfect for my home answering machine though! =)