ATI has a new product called the TV Wonder USB Here I dont know much about it except the last time I checked it was around $100.
Intel® Pentium® 4/III/II, Celeron® or other USB-compliant PC
Installation software requires CD-ROM drive
Cable TV signal or amplified antenna
Available USB port
Iteractive Program Guide requires Internet connection
TV browser requires Microsoft® Internet Explorer 4.0 or later
Operating Systems Support
Check it out, it looks like it should be what you want
Thank you for your answers, but these are not exactly what I had in mind. I want an external unit that connects over USB to the PC and is BOTH TV and FM tuner AND stereo. The one I already found is made by Hauppage but it's TV audio output is Mono. Maybe I'll have to settle with this...