No, no, NO! Verizon does NOT require you to have a data plan with "any" smartphone!!
My son, a college student, has a Palm Centro smartphone, and we do not have a data plan. We only have a family share plan. No one EVER even mentioned a data plan to us.
By the way, Blackberry gets all the attention and is perceived as glamorous, but it's an UGLY, bulky phone. My son's Centro is absolutely fantastic and does everything you'd want as an organizer (in addition to phone/text functions of course) but is much sleeker. I'll bet it has MORE functions than a blackberry.
I strongly encourage anyone who wants a smartphone, without the expensive data plan, to check out the Centro.