In the past I have paid a premium for functions, such as answering machine and fax capability. Now I just buy a basic modem, possibly with fax capability. I found I never used those other functions that I was paying for.

Some good modem manufacturers are Zoom (K56Flex), Supra (now Diamond) (K56Flex), Boca (K56Flex), Cardinal (x2), and US Robotics (now 3Com) (x2).

Faster connections are now starting to gain popularity.  The three potential types are DSL, cable, and satellite (forget ISDN).  There are advantages and disadvantages to each type.  DSL has a lot of potential, but unfortunately it's controlled by the telephone companies, who are greedy.  With DSL you're connected all of the time, but it requires that you be fairly close to a telephone switch.  DSL would win easily over competing technologies, but the telephone companies have never learned how to market and they've allowed many competitors into their territory based on their own greed.  Cable is the biggest threat to DSL at this time, but the biggest drawback is that the more people in your neighborhood that are connected to a cable modem, the slower your access will be. Over the next few years cable is probably the option of choice due to better marketing and lower cost by the cable companies, but as more people go to cable, the primary adopters will start looking for other solutions.  Satellite is another possible option, but is has the drawback that it is primarily download only, with upload still being done through a phone line.