I guess it really depends on how much you want to spend. You can get a decent bike for <1k dollars by going with Giant…but if you are looking to build from frame up I’d look at http://www.origin-8.com for parts/accessories and framesets. They have a nice carbon 29er that was named top ten 29er products of the year by twentynineinches.com
If you want name brand I’d go with a Giant.