Just a personal opinion:
So far I like my Blackberry 9700. Qwerty keyboard, form factor, good battery life. It suits me well. The OS already allows me to do things I want/need to do on a smart phone, so no complain on that area either.
As long as there are people who have similar requirements like mine, I guess the Blackberry platform will exist. ( Although probably it won't be under RIM anymore =p )
But then again my personal opinion doesn't really reflect the whole market's, so fingers are crossed here and there.
Also, I don't say I won't jump into other platforms, sometimes it's good to try new things once in a while =)
Don't flame me ah, just 2 cents at 2 am in the morning..