Thanks

The following characteristics distinguish one modem from another:
bps: How fast the modem can transmit and receive data. At slow rates, modems are measured in terms of baud rates. The slowest rate is 300 baud (about 25 cps). At higher speeds, modems are measured in terms of bits per second (bps). The fastest modems run at 57,600 bps, although they can achieve even higher data transfer rates by compressing the data. Obviously, the faster the transmission rate, the faster you can send and receive data. Note, however, that you cannot receive data any faster than it is being sent. If, for example, the device sending data to your computer is sending it at 2,400 bps, you must receive it at 2,400 bps. It does not always pay, therefore, to have a very fast modem. In addition, some telephone lines are unable to transmit data reliably at very high rates.
Voice/data: Many modems support a switch to change between voice and data modes. In data mode, the modem acts like a regular modem. In voice mode, the modem acts like a regular telephone. Modems that support a voice/data switch have a built-in loudspeaker and microphone for voice communication.
Auto-answer: An auto-answer modem enables your computer to receive calls in your absence. This is only necessary if you are offering some type of computer service that people can call in to use.
Data compression: Some modems perform data compression, which enables them to send data at faster rates. However, the modem at the receiving end must be able to decompress the data using the same compression technique.
Flash memory: Some modems come with flash memory rather than conventional ROM, which means that the communications protocols can be easily updated if necessary.
Fax capability: Most modern modems are fax modems, which mean that they can send and receive faxes.
To get the most out of a modem, you should have a communications software package, a program that simplifies the task of transferring data.
go here http://computers.cnet.com/hardware/1,10121,0-2295748-402-0,00.html?tag=lnav-56k&pn=1&ob=1&qt=&qn=&F1=0&F3=0&F5=0&F6=5&F7=0&F8=3&F10=0&F13=0

I have a supreaexpress 56i by diamond multimedia cost me about £30 on ebay and is great. my dad had the external one before i got mine and they have both never failed (unlike our isp ;) )

www.diamondmm.com

Dont get usb modems they suck, i couldnt listen to mp3s while on the net because any program which played mp3s closed the modem down!!! VERY STRANGE

diamond supra express was the best modem a couple of years ago.. then i got cable so i dont know if anything better has come along... there cant be much more to squeeze out of modem hardware though, they are all going to be dead soon