From a viewers perspective there is little difference between the two display types.  I won’t get into the exact technical differences between the two devices.  But there are many who find themselves at the local TV shop wondering which one they should buy, both have had significant drops in price lately and rumor has it that there is going to be more before the Christmas season this year.  Today’s 720P DLP and LCD rear projectors are no longer priced out in orbit, comparable deals can be found on both.  Both technologies are very good at what they do with only subtle differences in appearance it can be an intimidating decision trying to figure out which to buy. 

Sets like Samsung’s HLP4663W is a very good 46” DLP set based on TI latest series of DLP processors.  Sony’s GRAND WEGA line of LCD rear projectors like the KDFE55A20 makes for good competition from another display technology.  You can drive yourself crazy driving to more and more TV shops looking at more different sets to see if any of them are going to have that magical quality that your eyes love. 

My advice might differ from the orthodoxy you’ll get on many forums or even sales people who say to compare, compare, compare and trust your eyes.  Outside looking for a few specific details on a new TV, I don’t think viewing more TVs in store are going to do you much good.  Sure, you can see with your eyes standing in the store that the CRT based Rear Projectors (RPs) sometimes have color alignment problems, but can you really trust the TVs are even calibrated correctly sitting at Best Buy?  Even the high def feed from the local cable company that’s piped into an aisle of hi-def TVs might be sullied from being split too many times.  I’ve seen DVD players connected to display model TVs with a movie and the DVD player isn’t even setup to play at progressive scan, so the resulting image is horrible.  So, I don’t think you’ll get much out of looking at displays in the store.

But when deciding between LCD and DLP do some critical viewing, knowing what to look for in each display type will go a long way in helping you decide. 

Look at both TV types from a direct viewing angle, mimic being seated in front of the set, bend down on a knee if you have to.  All rear projector displays are designed to be viewed straight on.  This may seem like a limitation until you consider the average size of the family room and how huge these TVs get.  In your average viewing room a 50” set is going to loom so large it’ll hard NOT to see it straight on.

On the DLP make sure you watch something moving quickly across the screen, like a dogfight between two planes that scream across the screen, follow them with your eyes.  You can just flick your eyes across the screen while watching anything.  Do you see the rainbow?  If the rainbow effect is disturbing LCD is your option.  The rainbow effect is caused by the color wheel that presents equal amounts of red, green and blue to create all the colors you see.  If you move your eyes with the color wheel you’ll probably see the rainbow.  There is a percentage of the population who will see this rainbow all the time.  These people’s eyes aren’t easily fooled by technologies optical illusions and they probably have very good eyes.

When judging an LCD, look directly at a particularly bright image, lots of bright sand or white snow.  Does it look to you like you're viewing the images through a screen?  This is the screen door effect found on LCD projectors.  The screen door is caused by the spacing of each pixel on the LCD chip being amplified across the projected surface.  That handful of microns of space on a chips starts to get noticeable when projected to 50” or even 70”.  There are various tricks done with lenses and mirrors in newer LCD RP designs to alleviate this symptom but a certain amount of it is inevitable.  Between each pixel must run a circuit trace, even on the tiny IC chip that is the LCD, the circuit trace regulates voltages to activate the LCD itself.   

Those are the drawbacks with each device type.  Otherwise they're both great with nice, bright digital images.  Both will require lamp replacement from time to time which can about $300 but shouldn't need replacement for about 2 years or so.  The DLP has a "color wheel" inside, but this should be no louder than the fan that cools the lamp.  So, listening to each TV is important, you want to hear silence.  Well... neither will be completely silent because there is going to be a fan, on the DLP a color wheel spinning but you probably won't even hear the color wheel.  Otherwise it's up what you like the best.  Don't be too concerned about the macroblocking effect when looking at those HD digital cable feeds at the stores.  All sets will do this, it's not the sets fault, it's the video. 

Good luck and happy viewing.