Initially, Sony Playstation titles were 320x240, but I'm uncertain as to whether or not the standard/default has been bumped up to 640x480 now; possibly with the new generation consoles we'll see 640x480 and 800x600 as default. These resolutions may look cleaner on tv's, but not text. Most people have their computer monitor settings at least 1024x768. Notice that when you run a non-compressed video file (as opposed to a divx or compressed clip) that is 320x240, it's in a tiny window display. If it's in media player, right click and select the full screen option. Looks yucky doesn't it? Shows how much sharper a monitor is than a television.
ArchAngel, hdtv can handle a 640x480 resolution easily. The 1080 refers to the vertical lines. The actual res is something like 1920x1080, but again, that's interlaced. Some hdtv sets can do 720 progressive, but I think that as soon as Hollywood quits being greedy with control gestapo tactics like the Recording Industry, we'll start seeing movies on something like hd-dvd at 1080 progressive. I'm not holding my breath - it'll be another 5 years. By that time we'll be able to decode hdtv in software on our 10GHz cpus.
You can pick up a 65" hdtv set today for $3000. Within a few years, you'll be able to pick up a same-size, higher quality for closer to $2000. Why pay $1500 for a 21" monitor when you can get a 65" screen? Not many people want to bother with all the tweaking and setting up it will require.
Since hdtv is the big buzzword in video right now, all the video card companies are announcing their cards as being hdtv compatible. But right now, for one you still need an hdtv decoder card. It's kinda sneaky of the companies advertising hdtv compatible - it would be like saying back in 1997 that a video card is 3dfx compatible, you just need a 3dfx card.
Right now there are 3 cards that can give you hdtv on your system: Hauppauge WinTV-HD, AccessDTV and the HiPix card. They run between $400-$500. The cool thing about some of the capabilities is that you can record hdtv onto your hard drive! Of course, it averages at 9 gigs per hour.
Here's to hoping one day we'll all have dual setups - one display going to a 19 or 21" monitor (for text), the other going to a 65" hdtv (for graphics).
edit: fixed typo