I'm of two minds about this.
My group is very laptop oriented and everyone in it has one. Everyone brings theirs to the game as well.
Since we added a wireless hub a few years back, it started to get a little distracting at times - so much so we started bitching about it and the one player who would frequently surf during sessions when he wasn't the focus of things.
As time has gone on and one of our players got a new laptop, however, I now understand what the problem is with laptops at the gaming table:
It's the damn screen.
Physically, the laptop can divide the player from others at the table during play. And it is that division which is the Bad Thing.
I recognized this when one of the player's new laptop was a Gateway convertible notebook/tablet PC. He uses it in tablet form in portrait mode.
It is, quite simply, the greatest PnP laptop you ever did see.
It is the perfect reference book. He has the entire 3E library in searchable form on there. In portrait mode - the screen is as big as the page in the actual book and it's all very clear and very readable. It's very natural to use.
He still tends to use paper though - and since he got his Tablet he is the official initiative/hit point keeper for the group. All of those who comment on just wanting to use a pencil? Well with a tablet - you can. It's the best of both worlds and the paper never runs out. The handwriting recognition is actually pretty good - so if you later want to convert it over and copy paste into Word or Outlook - it's easy to do so.
So yes - the tablet is awesome for combat tracking - and it's the best pdf reader you could ever have in portrait mode. But the key thing?
It lies flat - like a book. It is essentially a PhB on the table.
And so the screen never gets in the way of the player or others looking at him across the table. It does not divide the player from the common game going on in the centre of the table.
And that, really, is the essence of the issue right there when it comes to laptops at the gaming table.
Moral of the story: if PnP is your thing, get a cheap
Gateway CX210 for $899. You will not regret it.