the thing that is key to what he said, is that he'd recommend going with a non 1080p monitor.
This is a monitor, not a TV, which means you want as high res as possible since you're most likely running it from your computer.
Second, from what most people report, ANY HDTV looks like crap on SD. This is probably a little worse cuz it's even higher res than a 720p, but to me that's an argument against buying an HDTV - which just seems strange.
You can get upscaling DVD-players to 1080i and there are already HD and Blueray players out there. They are expensive for the higher quality, but the price is only going to drop on those. You can output 1080i or 1080p from many video cards.
In terms on not having a builtin tuner, AFAIK the cheapest 1080p LCD with a tuner is the Samsung 40" which will be $600-700 more at least, on sale. You can buy one much cheaper than that to hook to this.
Finally, at this price it's cheaper than many comparable 720p sets so it just makes sense to get it instead. That way you won't have to buy a 1080p set in the future.
If all you care about is SD TV, you shouldn't bother with any HD set because it will look better generally on a cruddy cheapo SD set that is the native res for SD. If you're interested in HD, SD is a moot point because none of them will look as good on it. It comes with the increased resolution.
Also, the current gen video game consoles all output HD. PS3 outputs 1080p. While there isn't much going in 1080p right now, the next gen consoles after xbox360, Wii, and PS3 will almost definitely be in 1080p at least, and you'll want a higher res display.