Straight Talk recently announced the addition of their first Android phone, the Samsung Galaxy Precedent. Android phones are well known for syncing well with Google, so if you keep your contacts, calendar and notes in Google (my preference), you'll be in great shape with an Android phone. Or, if you prefer to keep those on your PC, you can probably find a way to sync your PC up to Google, then your phone will sync with Google as well, and you'll be all set up.
A little about the Precedent phone: it will be on the Sprint network, so if you've been happy with your service under Sprint, you'll get the same coverage with this new phone. The cost of the phone is $150, and the service is $45 per month (plus a few dollars in taxes) - that gets you unlimited talk, text, and data.