So now your telling me a MBP with FCP2 is no good for 'actual' editing and i need to get a MAC Pro... Sod this I'm doing small films not making bleeding 2hour long whistles and bells feature films...
I'm seriously looking at going with Edius...Macs seem to be more hassle than their worth...Mac pro's are to expensive and over the top unless your actually doing it for a living... 
Dive safe
Dean(headache)B
I use a MacBook Pro (Older 17" which does not have the RAM capacity of your machine and a slower/older chip) and us it to edit things all the time (DV, HDV/AIC and some ProRes). With an eSATA card and/or FW card you can attach external drives that should do the trick for what you want. Weibetech and others make enclosues of various flavors which work well. I have even done work on my old 1Ghz G4 which only supports 1 Gig of RAM and had a small (64 Meg) video card.
On the internal drive issue you do not need the biggest, but the incremental cost of getting a few extra gigs if you are BTO can be worth it unless you are a good DIYer. Apple's premium is not as bad for the mid-level drive upgrades, though the ump to the largest drive comes with a larger premium (as others mentioned the RAM from Apple is also at a premium) In the U.S. to go from the 160GB to 250 GB is about $150 and the hassle factor (for me) would mean I would just have Apple drop the bigger one in if it was a BTO. $700 (U.S.) for extra 2 gigs of RAM though is high since you get 2 Gigs more for ALOT less as places mentioned such as OWC http://eshop.macsales.com/MyOWC/Upgrades.c...s=Show+Upgrades.
You can find yourself running out of room unless you move some bits and pieces that come with the Studio (such as Gigs of audio files for Soundtrack) off to another drive. I do that myself often when I get jammed for space, but easier to have in one place on the machine if you can swing it. But overall as Drew said you want external storage for the media and other files. It is best to keep those things off the Application drives
Of course having an external monitor that is dedicated/calibrated NTSC or PAL monitor is a good thing to have for color corrections and in a Tower there are options for cards, but you can also have things such as the Matrox http://www.matrox.com/video/products/mxo/home.cfm which will work with a Laptop. On the other hand, you can also look at the scopes in Final Cut and get close enough to what you want, though a dedicated card/calibrated monitor (or the Martox) is always the way to go for broadcast on any system.
As Drew mentioned the apps will all work but Color (which is a new app and people have existed without it for a long time) needs another monitor. You probably have one around and when not traveling you can hook the monitor up if you want and besides you can have a larger workspace when you want that way.
I even have played around and edited/previewed Final Cut projects on an LCD HD TV via a DVI/HDMI hook-up.
Of course for the ultimate thrill a totally maxed out tower with all the bells and whistles is very cool, but not needed.
A bit off topic there are a couple of times when it is good to buy a Mac. One, probably 3-4 weeks after I buy one which means prices are about to drop 
. Two, right after major events such as MacWorld, which is early in January. New toys come out at that time which also means prie drops. I have not heard of upgrades to the MacBook Pros coming then (though there is a ultra portable rumor 
) but you may want to hold off.
Lastly, to save some money, refurbished units at the Apple Store (and on-line) are usually fine also. I have been buying more of these lately and they have been fine. Come with the same warranty and if there is an issue Apple is usually very good to help.
i suppose i could take a trip and come back with a new baby... if its worththe journey...
