Sprint: Contract Upgrade Question

[NighthawkIX]

Time for a contract renewal from Sprint- been a customer for 4 years now.

Currently on a old-school Sprint Fair and Flexible Family 550 plan with 3 lines for $79.99.
One of the lines has the "Sprint Unlimited Data Pack" add-on for free (bonus from my last renewal)

Unfortunately, I talked to the Sprint Reps today about upgrading to either the HTC Hero, or waiting on the HTV EVO, and I've been told those two phones will not activate on my current plan. Can anyone confirm this?
It currently looks like Sprint is trying to squeeze me into buying the $129.99 Everything Family Plan... There is no way I want to pay that much for phone service, but at the same time I want the Hero or EVo.

Also, what kind of bonuses can I get from renewing my contract with Sprint? Currently they're just offering 1 month free for the first line, and $50 credit for the second 2 lines. Any advice here very appreciated. Thanks