I'd skip a full size tripod. Consider the Pedco Ultrapod. I liked it a lot better than the Gorillapod that I had. The larger of the two models would be best for your DSLR. Personally I'd take another lens before a tripod though.

Just my opinion, but I never especially liked the 50mm look. If going with prime lenses I'd be inclined to take a wide angle first, a short telephoto next, and leave the 50 home.