We have the old family plan rate of $49.99 for 2 lines, 1000 mins, and unlimited T-mobile to T-mobile minutes. I don't want to give that up.

I haven't found anything that even compares to that anymore.
To add on the Blackberry email and web access it'll be $19.99 a month. It doesn't include text messaging, but I can have that added for only $4.99 for 400 messages/mo.
The Sidekick plan is only $19.99/mo and it includes unlimited email, web and text but I don't know that I'm crazy about the phone. I worry about the durability of the flip around screen.
Have you noticed any improvement in your coverage? T-Mobile has been advertising improved service, but maybe that's just here in AZ. Also, did you try the opera download that NM suggested? Will it allow for LoT access?