Thinking of buying my first Mac, i have questions...

I currently work from home doing graphic design work and im thinking of buying my first MAC. I hear Adobe Photoshop and Illustrator work better on a MAC and also im just getting sick and tied of my PC crashing all the time. I've been a PC user all my life and dabbled on MAC's here and there, so if i do this its going to be quite a change as i currently sit in front of my PC over 8 hours a day everyday.
A part of me feels like like im thinking of going to the other side

Now i can afford any Apple product i want, but at the same time there's a big cheap-o in me that cringes when i see the $2500 price tag for a top of the line 17" MacBook Pro. Which is what i am thinking of getting for my home even though i love the new iMac's all in one just one plug to plug in man are they sweet!

The thing is, i love to travel,..
I know conventional wisdom would say, 'if you work from home get an iMac, then if you go on the road buy a MacBook',.. but what my unconventional mind is thinking (since i have a big 22" Apple Cinema display already) is why not get a MacBook Pro and basically use it like my current PC tower that sits next to my desk. Literally just set the MacBook off to the side, hook my Apple Cinema display to it, as well as wireless keyboard and mouse, and use it as my main home work station without even touching it,.. then if i travel ill have the ability to unhook it and take everything with me. Might sound crazy to drop $2500 on what will be primarily a home work station when i could drop only $1600 on an iMac to do the same thing, but if it keeps me from later buying a MacBook Pro it will save $1600.
So my first question is what do you think of my above plan from a graphic designer mindset? Would it work reliably? Is it something that should be done? The guy at the Apple store i talked to said the MacBooks are powerful enough to run photoshop and illustrator but will they run it comparable to a new iMac? The specs are very similar so i think so but id like input from those who have used both.

Lastly,
What's this i hear about Intel based MacBook's being able to run Windows? Is that true? If so how would that work? Would you need a copy of Windows XP and would it be like a dual boot OS or what?

This might be better in the switchers forum.
If you have the money I think you should get the macbook. They work really well when it comes too using the apple cinema display. They're almost/just as good and powerful as the imacs, and like you said good for travel. Its a lot easier i think to keep one computer I have two but its easiest to use just one for files and email and such...
For running windows, they all can run windows using bootcamp(comes with any mac) which would be the dual boot you can choose which to boot into, but you do need a copy of windows and you would need to partition your hard drive for a windows part and mac part. Also you can use a virtual machine,parallels or vmware fusion (also needs a copy of windows) which would run windows while you're running your mac, the only down fall is that it runs significantly slower for obvious reasons, but at least you don't have to reboot just to switch, and you DONT need to partition you hard drive when using parallels or vmware fusion.

I use my Macbook Pro at work daily with an external display and an attached keyboard and mouse. I also run Windows via Fusion and Parallels (depending on the computer I'm using). It works great. Virtual Machine or Bootcamp decision I think depends what you're going to use Windows for. If it's for Photoshop/Illustrator etc. I'd recommend Bootcamp. If it's for more lightweight apps, a VM should suit you fine.

Since you mention traveling, and if you only want to buy one machine, I'd say go with the MacBook Pro.

Photoshop and Illustrator are almost identical on both Mac and Windows. I don't see how one if better than the other at all.

The only big difference is that you can see your desktop while you are working on the Mac version.