In the past, plasmas were superior over LCD TVs when it comes to picture quality. That said, as LCD TVs become better as technology advances, the gap now is marginal at best. To decide on whether you should purchase a plasma TV or LCD, you should look at how you are planning to use the HDTV.

If you plan to play a lot of console games on your new HDTV, you should choose an LCD over a plasma TV. Even though not as big an issue as it was before, plasmas are still relatively prone to screenburn and image retention which could be accidentally brought upon by a long gaming session.

Besides, LCD TVs tend to be brighter and boast a higher panel resolution than plasmas within a similar price bracket, meaning that the games would look more vivid and detailed, resulting in an absorbing gaming experience.

The same case applies if you are going to use a home theater PC (HTPC) with your HDTV. The higher panel resolution of LCD TVs will ensure that the text on the screen are highly visible; and the increased brightness level (compared to plasmas) is important in mimicking a computer monitor. Besides, if you sit closer to your HDTV you may notice a lot of pixel noise on plasmas because of the fashion the images are rendered through pulse width modulation (PWM).

However, if you enjoy a lot of fast paced sport programs, a plasma TV should be a strong contender in your consideration. While much improved compared to previous batches, LCD TVs still suffer from motion ghosting due to the sample-and-hold phenomenon which is unavoidable in the LCD technology. Newer LCD TVs powered with motion interpolation technology (100Hz and above) are better in this aspect, but as the technology has not been perfected, it is generally limited to smaller screens (less than 40”), and processing artifacts like shimmer and motion tearing are occasionally detected.

I realize I mentioned before that there's hardly any difference in the picture quality of plasmas and LCD TVs these days, but taken as a whole, the blacks and shadow detail on plasmas are better than those on LCD TVs. So if you are an avid fan of movies with lots of dark scenes (for example Batman Begins and The Prestige), you should seriously consider a plasma TV over an LCD.