It's not just the size as to whether it'll sit on the table well. It's also about general practicality if you're seriously considering fully portable use of a laptop. With the 17", you're inevitably going to be bumping into things, whacking fellow passengers, etc. It is a thin but large beast, no getting around that.
So it becomes about whether you actually need 17" on the move, or whether something you want is just the core of a transportable desktop, but not having to carry a large laptop around with you.
My own ideas about this have changed a lot in the last 10 months that I started being a Mac owner and certainly in the 6 months that I've had the 17" MBP. I've had a lot of technical issues with the MBP and that really interfered from thinking about optimum usability - I had to concentrate on just usability. Same with some of my other Mac hardware purchased this year, but the Intel Mac portables have been undoubtedly the POS'iest laptops I've had in the last 6 years.
Anyway, having finally tired of using the MBP as my primary machine I carried on the thinking that I will probably need to carry everything around with me - so I replaced the 17" MBP with the HP NX9420, a technically virtually identical machine, only under Windows. However it's turned out not to be the optimum in my case. Because when I shuttled to and forth between the various places I work, I have already procured large monitors and keyboard/mice for each location.
What I finally realised was that all I needed was a relatively compact laptop which was easily dockable with monitor, keyboard and mouse (and LAN, etc) in order for me to work with it as essentially a full desktop.
So my final solution for this year are relatively compact Dell Latitudes with the D/Port docking stations. I'm grateful for the knowledge I gained but I really am glad to see the back of Mac notebooks as my primary machines. The D/Port system allows me to move a 'normal sized' laptop around various sites, use them on the move (in a more effective / usable way than a stock MBP despite the inferior OS and fugliness - because the hardware is superior) and yet dock them in one step and effectively have a 'proper' desktop PC.
The Macs, lacking Dell's elegant D/Port interface will be necessarily a bigger hassle to use in this way but the 15" MBP combined with an iCurve and an ACD + Apple keyboard at each location (you can carry a wireless Mighty Mouse with you) that you would call a base would be in my opinion, a smarter way of working than lugging a 17" MBP around with you all the time.
If any of that's hard to read I'm really sorry, but I just typed that up in one go and I've had too much booze (at 6pm my time? yeah, bad isn't it) to really go over it again.
