Which protein supplement? Relative newbie to weights

Stu-R

Hi,
I'm relatively new to weight training (only been doing a dedicated programme for about 10 months now) and could do with some advice on a protein supplement.

I'm 34 yrs old, 5'11, 190 lbs. I train at least 4 times a week, often 5, and occasionally 6 times. My job means it's really difficult for me to keep a consistent training schedule; I work late hours and undertake frequent european travel however, when I have a good run of being at home (ie: not travelling) I can keep up a training schedule of 5 times per week for a run of about 5 weeks until the next 1-2 week work trip interrupts the schedule. It does mean I can do more cardio work when I'm away, providing i can fit it in at the beginning/end of each day that is - not easy when your work colleagues are all beckoning you to the bar!

I've been reading up on as much as I can concerning Protein supplements, including all of the information listed on this post:
http://www.musclechat.co.uk/about5927.html

.....and am still confused

What supplement would you guys recommend for me?
Currently I am taking a morning and evening (post workout) intake of the Protein shake available from Holland & Barratt - it is their own-branded offering.

Aside from the protein content, the important ingredients I would like are anything that will help boost my immunity and help manage stress levels (eg: Glutamine) and help recovery time. As I'm not knowledgeable about all of the other amino acids, peptides and so on, I'd appreciate any guidance. Money is not an issue, I want the best supplement to benefit my training

Thanks, Stu