Apple's 17" Powerbook becomes uncomfortably hot in your lap. Same goes with the XPS Gen 2/XPS M170. If anything, the "Hybrid-DTR" Qosmio G20 is better for his fertility (and... who wants to become infertile anyways :P).
Having been using a XPS Gen 2 for the last 5 or 6 months, I like it, but I actually don't use the potential graphical power as much as I'd have thought I would 5 months ago. Don't get me wrong though, the 6800 Go Ultra is a beast in most modern games (though the 7800 go GTX is even moreso). I played the F.E.A.R. demo at 1440x900 with all settings set to medium, minus physics, which was set to maximum. It was "pretty" playable at about, subjectively > 20FPS average (for some people, this is arguable - they require 1337 > 60 FPS in any game, with all the bells and whistles on). If anything, I use it more of as a general notebook (which one can hardly call general, given it's 8.4lb weight) that I cart between home and school (which will be sure to have some consequence on my back in future years). Makes me wonder if I should have considered a tablet PC instead, like the Tecra M4. Or an ultralight portable one, like the Dell X1 or the 700m, or that Acer lightweight, or more recently, the Toshiba Libretto. All of which would suit my current needs much better than this hulking beast of a laptop.
Also, having a laptop running at 1920x1200 on a 17" screen can really strain your eyes. So, unless you have very good eyesight, I'd avoid the XPS M170 because the native resolution is too large. 1280x800 is too big for the real estate offered by a 17" screen (text wise). 1440x900 is a sweet spot. 1650x1080 may be too small. However, widescrreen resolutions are definately nice to have on a notebook. I'd never buy a normal 4:3 ratio notebook unless the reasons for outweighed it.
Another thing is that MCE 2005 is sorta a resource hog, due to the ehome, escheduler, and the entire media centre set of services. Granted that the Qosmio G20 has it standard, whereas the M170 has the option of moving to professional or home, the M170 would win here. Media Centre is only good if you want to use your notebook as a HTPC (Or rather, HTnotebook).
Also, what people have said about 2 hard drives is true; it will decrease the amount of battery life significantly. However, you could take one of the hard drives out of the Q20, thus eliminating that problem. I don't see how you will need more than 60GB if you are just using it for general purpose computing.
Designwise, the Qosmio wins by a longshot. The black glossy surface is *nice*. The blue LEDs are *nice*. The slot loading DVD drive is *nice*. Almost everything about the notebook is nice. Save for the stickers, which I absolutely hate. However, like people have stated, the glossy surface is very much prone to fingerprints. So, if you want the notebook looking like a solar panel, then you will have to have a cleaning cloth at all times. The M170 Silver thing at the back is just ugly. Same for the selected Silvery-Grey part of the notebook. I would have preferred if it were all black. The LEDs are unnecessary glamour. The Dell/XPS logos on the Gen 2 are ugly and intrusive (not sure if they are still there on the M170).
I'm not sure about technical support from either company, so I can't really comment on that aspect with first hand knowledge. However, from what I read on the forums, Dell techies are, well, loaded with BS. They're just as bad as people who don't know what the hell they are talking about. Occasionally, you'll find somebody who understands, but that's far and few (this is based on a general view of the techsupport sector). Toshiba, well, definately don't know anything about them.
Regardless, the point I try to make is that he is looking for a basic notebook with some sleekness and power, and not some uber gaming rig. Thus, the needing of the M170 is completely unwarrented, IMO. He'd be better going along with the Qosmio, or maybe the Inspiron 9300, as someone had mentioned, with X300 GPU and 1.73GHz Pentium M, which would be far cheaper. (note that I9300 is still nowhere near as sleek as the Qosmio. And will never be.)
In fact, I'd actually argue against a 17" notebook. I'd recommend something more portable, thus being a little bit more functional, minus the Powerbook 17", as someone else mentioned - the unpleasant cooking effect, and the fact that it's OSX, which in turn means buying all new software and getting used to a new OS. The I6000 doesn't look too shabby for your requirements, nor does any 15.4" laptop.
Yet, if you are serious about buying a 17" notebook, I'd reccommend at least looking at the Acer and Asus offerings, as well as the other Pentium-M/7800 Go GTX combination ( http://www.gamepc.com/shop/systemfam...?family=noteb5
). Or Sony if you want sleekness (albeit extremely overpriced).
Oh, and just ignore anything with the phrase "Pentium 4" or "Athlon 64 DTR" or "Athlon 64 X2" in a notebook, cause those are just hints for > 10lb laptops. (Generally.)