Mountain Biking - Choice between bikes

Ok so here is my dilemma, I want a bike for fitness, commuting, and mountain. My commutes would be less than 3 miles one way at most. Should I a.) Buy a road/hybrid bike i.e Specialized Sirrus http://www.specialized.com/bc/SBCBkModel.jsp?spid=32215 b.) Buy a mountain bike i.e. http://www.specialized.com/bc/SBCBkModel.jsp?spid=33092 or c.) buy both. I am hoping to spend less than $1000 give or take. I will not be doing anything too extreme atleast not right away, and what I am afraid of is buying one bike or the other and then being upset. Any opinions?

Ok so here is my dilemma, I want a bike for fitness, commuting, and mountain. My commutes would be less than 3 miles one way at most. Should I a.) Buy a road/hybrid bike i.e Specialized Sirrus http://www.specialized.com/bc/SBCBkModel.jsp?spid=32215 b.) Buy a mountain bike i.e. http://www.specialized.com/bc/SBCBkModel.jsp?spid=33092 or c.) buy both. I am hoping to spend less than $1000 give or take. I will not be doing anything too extreme atleast not right away, and what I am afraid of is buying one bike or the other and then being upset. Any opinions?

If the commute is not too far (like 3 miles), I'd opt for the mountain bike simply for the sake of being able to do everything.

If the commute is not too far (like 3 miles), I'd opt for the mountain bike simply for the sake of being able to do everything.

I concur.

A hybrid is like an above ground pool.

A nice hardtail would work well for ya.

Gastro, don't be harsh. My above ground pool has a slide and the little mermaid on it.

A nice hardtail would work well for ya.

Gastro, don't be harsh. My above ground pool has a slide and the little mermaid on it.

Alrighty then what do you think is better between Rockhopper Comp Disc and the same bike but 29er

If you have the opportunity, ride both. What will your off road riding be like.

not sure im pretty new to this. I would imagine it would be mainly easy to moderate trails if that means anything.