Plenty of good recommendations above, so I'll just add my own ideas for another view.
I also have a cousin with a similar "problem". He's not nearly as tall, but has always been extremely skinny until he started lifting and working out. Putting on size and gaining was difficult since his body basically burned everything. He originally went with mass gainers, which worked fine, but were very expensive (a full year of on and off supply would easily be a few hundred dollars... not including protein). He recommended a DIY fix.
Mass:
1) He bought some carb supplements (search "carb", "complex carb", etc and you'll find a handful)
2) large bags/buckets of quaker oatmeal, plain
3) peanut butter
4) someitmes add in other nuts (walnuts, almonds, whatever you like, etc)
Mix 1+2+3 plus some protein powder (or even without protein) for a heavy shake without too much bad fats.
Protein
For proteins, personally I use optimum nutrition 100% whey. It comes on sale regularly at either GNC or Amazon for ~$55 for 5lb (60+ servings, I believe). Good reviews, and nothing fancy. Just low fat whey protein. Good to add with some of the items above if you need the extra calories.
Creatine/other
Personally, I think this is more of a temporary thing. As soon as you cycle off the stuff, you return to normal very quickly. It may help during a brief bulking period, or something like that, but not really a long term solution. GO with brands that make solid products elsewhere, although you'll get plenty of suggestions. Optimum nutrition and USP labs seem to generally make some good stuff, although there are many others.
The real long term solution is to continue eating plenty of high quality carbs and protein from food sources, not supplements. I'd encourage you to not get more than 20% (average over a month) of protein and/or carbs from supplements, as your body simply doesn't process that as effectively as some kind of food. The shakes and all are good meal replacements on occasion, but don't really solve much.
Happy gainz!