I think the best and most cost effective thing would be for one of your team members to be a hardware expert.
I myself don't know much about hardware, but my brother knows the stuff inside and out and I have him for advice. I thought I had a fast PC, and then he built another one for me for about $1000 bucks and it is literally 6-8 times faster. Building your own machines is not only cheaper, but it allows you to upgrade the individual parts as needed and keep them always top of the line at minimal cost.
One of the problems with prebuilt systems is that the companies (especially dell) will always try to cut cost one way or another, usually with crappy video cards, power supplies, or motherboards. A cheap power supply might now sound like a big deal, but if later you realize you need to add another drive or another device to your workstation, you realize you don't have enough watts and you're stuck.
When it comes to monitors, quality varies wildly, and none of the specs provided by the manufacturers are reliable. the best thing to do would be to go to hardware boards and look at people's reviews.
Is a pretty good source.
Tablets are vital.
Dual monitor setups are vital. But you can afford for only one of them to be quality and the other to be generic. I have a Planar PX2611W (26"), and second crappy 19". The planar is a very good monitor but also pricey. I managed to get mine on sale at some point for $500.
You must, must, must, have a good reliable central server that is accessible via the internet, where everyone stores their files. My brother set up a Unix server for me and it is a freaking thing of beauty. It's got tons of space, it does regular back-ups, I can access it from anywhere, and it's independent of my main system OS.
Good Chairs. You'll be sitting for a while.
Licensed copies of all the software. This will probably be your biggest expense of all.
Hope everything goes well.