Is the Xbox 360 HD-DVD drive worth it for use with a computer monitor?

Well if you want to watch HD DVDs it will be better than a normal 480p TV. but HDDVD isnt going to go anywhere, so in a couple of year they probably wont exist anymore.

That sounds like 1080i to me. I think you are correct on that fact. I would say do not spend the 180 dollars.

The start up cost would be 180 + tax(over 15 dollars minimum)

and then $25 - $40 per HD-DVD. You should just stick with regular DVD's on your 360/other DVD players. The cost is too much.

Even the best HD - DVD's only sell a couple hundred thousand copies, and that is very low in sales compared to regular DVD's. The quality is worth it, but you should save your money.

No. If you were using a larger widescreen, maybe... The 360 itself does a decent job upconverting regular dvds. I don't think you'd notice that much of a difference...

The HDDVD format seems to be losing the war against Bluray, too.

Oh...and 1080p is 1920x1080.

No. Why? Because HD-DVD is a doomed format. You're just going to waste 180 bucks. Right now, only 3 of the major studios support HD-DVD (Universal, Paramount, and WB). WB have already said that they're going to go Blu-ray exclusively in May. And as part of the contract, if WB goes Blu-ray, Paramount (which used to support Blu-ray and HD-DVD, then switched over to HD-DVD because Toshiba paid it 150 million to make HD-DVD movies exclusively for 18 months) can opt out of its contract, and go back to making movies in whatever format it wants. It seems like Paramount is leaning towards Blu-ray. Universal is not going to be able to keep HD-DVD floating. Save your money and get a PS3 or a Blu-ray player if you want to watch HD movies.

Since you only have 1080i it really isn't worth shelling out the extra cash.