Advice on NP5175/W170HR Options

I searched a good 20 minutes amount before making this thread to try and figure out if this was the right place to post this. As far as I can tell questions like this are to be posted in the general section, but I've already settled on the brand and the reseller (either Xotic or Myth) and have a specific question regarding CPU choice for the "Sager NP5175 / Clevo W170HR" seen here.

What I Do

I am a graphic designer. I do most of my work in Illustrator, InDesign and Photoshop CS5. Occasionally I do some web design/coding and some light video work (basically extracting video from a DVD, converting formats to make sure people can play it, etc). I don't do any huge 3D rendering or super-intensive simulations. I often have 2-3 CS5 programs open at the same time, and lots of browser tabs (some running google docs).

How I Use the Laptop

This laptop will be used primarily at a desk at work, but I also take it to people's offices, meetings and presentations. I went with the Matte screen because being able to take it to show my work to a client is important and I don't want it to be ruined by the glare.

Why I'm Upgrading

Currently I'm using this laptop, which I've upgraded with an SSD and 8GB of DDR3 ram, hooked up to a Dell 24" UltraSharp monitor.

It was working mostly fine but recently I've started doing a lot more work in InDesign on 50+ page documents and handling the document is just too unresponsive for me. I've turned down the display quality settings as much as possible without removing transparency but that hasn't helped enough.

At home I have a Athlon X4 965 black CPU with only 4GB of DDR2 ram (same SSD) and 9800gt gfx and working in InDesign is heavenly compared to my laptop. That, and the heat issues I'm having with my HP laptop is why I'm looking to upgrade.

My Question

This is how I have the new laptop configured. I plan on taking the SSD and ram from the HP and installing it in the Sager myself.

This comes out to a little under $1200 with shipping which is nice. The main question I have is about the CPU. I care mainly about performance, but also a bit about heat and noise.

From what I understand and based on what I see in Task Manager, CS5 programs don't really use more than one core (Photoshop supposedly does, but I haven't done enough heavy work there to test it). For that reason, I assumed that the higher clock speed I get from the i5 would provide more performance than the extra cores in the i7. Is that accurate? Are there other advantages to using an i7 processor that justify the cost?

The other issue is heat and noise. I assume the i7s generate a lot more heat since they have twice as many cores and use more power. Is that true? I've never owned a Sager/Clevo before and I'm not familiar with the cooling/ventilation design on these models. One thing I really hate is the laptop making a giant amount of noise when all I'm doing is browsing the web on chrome with a few tabs open.

Another concern I have is battery life, although since I work mostly at a desk it is not a big issue. I would however, like to have a 2hr cushion on that, because sometimes meetings last that long and I don't want to have to lug a power brick with me to meetings.

I'm about to put in the order today or tomorrow, so any advice you guys could give would be very much appreciated.

SHORT VERSION:

I'm getting a NP5175, to use mostly at a desk doing work in Illustrator, Indesign and Photoshop CS5. What CPU option should I go with? I care mainly about performance in those applications, but I also do care about battery life, heat and noise, and value for the money.

P.S. If based on the above, you think that I'm making completely the wrong choice and you think there is a much better option (from any brand/seller), please let me know. I'm willing to go up in price if the gains are worth it.