I'd say you've got a shot everywhere, the top 3 will be a stretch, the next 3 will be a decent chance and the rest a pretty good chance. I wouldn't apply anywhere you don't want to study. Some folks blindly apply by rankings, that doesn't make a whole lot of sense to me unless you are just shopping for a diploma, but presumably you have things you are interested in and are actually looking forward to learning stuff. In that case, the rankings give you a general sense of how bright your fellow classmates will be, but they don't tell you much about the style of the school or how good its faculty are in your specific areas of interests. I only applied to four schools and they were all schools I'd have been happy to attend (and no, they weren't the top four ranked schools). I'm stubborn enough that if I couldn't have gone where I wanted, I wasn't going (at least not then).
The other argument is to apply to a bunch of schools, see where you get in, then decide which ones you'd actually be happy attending. For me, its easier to narrow down the field first and save the expense and work of applying to schools you know you'd turn down.