Hmm. There's some misinformation in this post. Let's try to clean some of it up...

DLP: sharp, bright picture. Only one part needs maintenance (bulb).

While the bulb is definitely one part that needs maintenance, it's not the only offender. Single-chip DLP projectors (those with a single digital micromirror device) rely on a rapidly rotating color wheel with color filters to deliver a color image. Moving parts = potential point of failure. Noisy color wheels are a common source of complaints.

In addition, the light engines themselves can suffer failure of one kind or another. There are numerous threads at AVS forums detailing light engine problems from various manufacturers. For example, Samsung DLP rear projection units seem to be plagued with a shadow problem...it's believed that the adhesive used to attach one of the fixed mirrors to the "light tunnel" eventually fails which causes the mirror to slip and a shadow to form. Since a replacement light engine will cost upwards of $1200 to $1500, buying an extended warranty for a projection television is a good idea.

LCD projection (LCoS): quality of LCD with size and reliability of projection. Sony (perhaps others) use three LCDs, one for each color light, to prevent "rainbow effect."

Careful. LCD (liquid crystal display) and LCoS (liquid crystal on silicon) are two different display technologies. LCD projection is just that: it uses one or three LCD panels with a bright backlight to project an image. LCoS is kind of a cross between DLP and LCD. Like a DLP, it's a reflective technology: you have a mirror-like surface that reflects light but instead of having tiny moveable mirrors like a DLP's DMD chip, you have liquid crystals deposited to the front of the mirror that you turn on or off as you would do with an LCD.

HD-ILA: triple DLP chips removes "rainbow effect" of single DLP (see below). Otherwise same benefits as DLP. (This is a new technology that to my knowledge only JVC has this at this time.)

No. "HD-ILA" is JVC's name for LCoS. It is a competitor to DLP. Sony's version of the same technology is called "SXRD". There are a few other manufacturers as well but Sony and JVC are the two gorillas championing this technology. You are correct that it's somewhat newer technology than DLP. You are also correct hat HD-ILA (and Sony's SXRD) features 3 LCoS chips and is thus immune to the "rainbow effect."

I'd like to mention LED-based projection lamps. This year Nuvision and Samsung introduced rear projection DLPs that use arrays of LEDs instead of a high intensity discharge lamp. There are several benefits: 1) the LED lamps last much longer than normal lamps; 2) the resulting color gamut is supposedly wider; and 3) there's no color wheel -- colored LEDs are cycled very, very rapidly. So rapidly, in fact, that the rainbow effect should be nonexistant. There are at least a couple downsides: 1) that LED-based units are somewhat dimmer than their normal-lamp counterparts and 2) LED-based TVs seem to require more tedious calibration once installed in your living room in order to get the most out of them.