I guess I'm one of the very few who use a Macbook Pro laptop. As far as processing and RAM it is more than efficient for chasing - and working the photos and videos afterwards. I've got 3GB of RAM and a 2.33GHz processor in my machine. Plus I think Macs are far more reliable and that can REALLY come in handy...
LOL from being one of the rare ones, its more unexpected to see someone with the same specs as my macbook pro for chasing as well. 2.33 17in macbook pro. Thing is a rugged one too, went through a car crash setting off the airbags, when i looked over to see if the thing was alive, it was on and still running!!
My laptop mount completely broke and the computer took a huge dent right in the air card slot, best place on the laptop to take a hit, anywhere else and it would of cracked and destroyed some part of the IO or logic board.
Whats best about it is the Dual boot of Mac OS X or Windows XP natively.
When i'm on the road while traveling to a chase etc, and want to listen to some tunes and upload my stuff into Final Cut, weatherTap, i use OS X, then when i'm in the heart of chasing, i switch over to Windows XP to handle spotter network, weathertap, GPS,DeLorme and any windows apps.
Then i got the 3.3ghz iMac at home to do all the editing and video converting at home.
Even though the Macbook Pro is great, i really prefer to buy a cheap Netbook or Dell or old MacBook, Chasing really beats computer to the dust.
Even though the computer survived the car crash, a quick peak under the hood showed how the heat and vibration of chasing had loosen every connector and screw, put massive amount of dust, and the thermal coating for the processors was very much well eaten away leading to many CPU overheats and core shut downs. Luckily, all was a easy fix.
So overall pick a computer that if it breaks due to stress, you won't be crying, and pick one thats got enough power to handle the things you must do while going 70MPH and not slow you down.