So you know what materials you need ahead of time instead of running down to the nearest or furthest camp or workbench?

Would make it a lot more convenient on hardcoe, instead of having to write down or memorize all the ten-billion recipes and ingredients you need.

Has this been suggested yet? Anyone agree?

Agreed. Perhaps like recipies you could find around that load up into your PipBoy.

Also it would be good to have crafting mats listed in a separate tab.

They are all listed the Prima guide, but once discovered it would be nice for them to be in the pipboy

I don't want to refer to my guide every 10 seconds though when I come across some loot.

I use it as a reference, and really only reason why I got it was because it was a collectors item.

Is this guide you speak of in-game? I noticed you can find copies of "The Wasteland Survival Guide" around, that kinda made me feel happy...

No. it's book to purchase.
http://www.amazon.com/Fallout-New-Vegas-Collectors-Official/dp/0307469956/ref=sr_1_4?ie=UTF8&s=books&qid=1287696429&sr=8-4

agreed, i would also like this. currently i keep a pad of paper handy and write down the materials I'm looking for because i forget what I need easily.