Originally Posted by SuperFatDave

BTW, a 29er "dualie" is kind of a beefy hybrid.
A 29er mountain bike is adifferent story.
I think that the suggestion that you find out what your rental was is a great one.
Otherwise, I recommend that you speak to the manager at said shop and explain what you want ... if he recommends a hybrid, ask him why.
At given price points certain models of different brands may have the same component/simailar part spec and the same/similar frame materials ... they are all the same is a poorly worded way of saying it, but in some cases not exactly untrue.
If the shops in your area have everything then test ride a mountain bike w/26" wheels, test ride a mountain bike w/29 inch wheels and test ride a hybrid or a duallie. It will tell you a lot about what you want as well as what you don't want.
I would recommend that you avoid purchasing a bike on the internet do to the cost and complication of doing so, when you have many shops in your area to choose from.
Also, do you have any friends who are knowledgeable cyclist or worked at a bike shop? If so, they may be able to assist you in determining and communicating exactly what you want and more importantly helping you find it