Butch,
Haven't explored laptops recently, so don't know if they make them with Core i7 processors yet. That's the proc (940 or 965) I am looking at for an additional "under-desktop" box for HD.
Tom

I have a similar HP laptop. Overall I really like it. If you are going to spec it out on the HP page, here is my advice for specs:

There are some good deals at places like B&H, Costco, New Egg, etc. You'll get more for your money than you will at hp.com.

Get 4GB RAM expandable to 8GB. 8GB is too expensive right now because it needs to be done with two 4GB chips, but in the future you are sure to want it.

Get at least a 320GB hard drive. There are two drive bays in the 17" HP laptops. There is a discount version at Sams Club that has two 250GB drives for a total of 500GB. You are better off getting one 320 and adding a second 7200rpm drive yourself in the future.

Get a version with a 512meg Nvidia graphics card.

Get the Blu-ray drive rather than the Lightscribe DVD+-R.

Forget the TV tuner unless you see yourself plugging in either an antenna or a cable TV wire.

The finger print reader is useless. Don't get it unless it is part of a bundle you can't live without.

Get the 64bit windows version. Eventually 64 bit Vegas is going to work properly.

Depending on how HD you are and how good your eyes are, you might want to consider the higher screen resolutions. I have a base 1440x900 model which works fine for 1440x1080 HDV, but if you are shooting in 1920x1080, a higher resolution screen will show you what you are actually shooting at full resolution. On the other hand, on a 17 inch screen, unless your eyes are really good, you aren't likely to see a difference. In any case, be aware of this when you are looking at systems.

A real advantage of HP laptops is that they work well with HP docking stations so you can alternate between a permanent and mobile setup with ease.

"the machine will be used for Vegas SD and future HD editing (currently Vegas Pro 8), Photoshop CS4 and similar graphic intensive software."

Besides the obvious biggie for NLE, CPU power -- the next obvious consideration is screen quality.

Go into the big retailers, take some of your own media on a usb drive (those preloaded videos of the bear, lake, and butterfly are caca), and compare the images on the screens side-by-side until you find the brand and size you like. If you are going to be staring at this thing for hours at a time and making critical decisions as to colors, levels, and the like, it had better be right from the get-go.

There are lots of highly-rated laptop brands out there with mediocre screens. Given the uses you stated, if you get one with a so-so display, none of the other bells and whistles are going to make up for it. I have an average laptop with a great screen, and every time I go into a store I am reminded why I chose it.

If you need Firewire/1394, be really careful that the model you choose is equipped. Many recent 17-inch HP laptops do not include the interface. It depends on whether you upgrade to a more capable graphics controller. Looks like the HDX 16t you reference includes it.

Be aware that with Vista 64, you may not be able to capture from a given camcorder to a given computer even if it has firewire. I have to go back to an old desktop to capture from my HVR-Z7 for instance.