This is based on my experiences with an unlocked E71-2 NAM. I'm warning you, I dunno anything about StraightTalk, or their branded E71. Hopefully you'll find some of this helpful to you:
To get Google Contacts on your E71, you can use Mail for Exchange (MfE) [http://www.google.com/support/mobile...&answer=147951], but I'm pretty sure the MfE allows for only one exchange account at a time. In other words, if you're syncing to google, no work email. A good alternative to MfE, especially if you're not interested in up-to-the-minute changes and updates to your address book, is SyncML. SyncML is built in to S60, and Google still supports it [http://www.google.com/support/mobile...n&answer=98230]. Since SyncML updates are manually executed (unless you use something like Swim [http://code.google.com/p/bergamot/wiki/Swim] to schedule them. Just saying you can, I never did.) you will help save your battery life. Using SyncML will also free up MfE to sync to your work email.
There is a free app called Nokia Messaging [http://email.nokia.com/account/home.action]. It supports push email for Yahoo, Hotmail, and GMail. Just email though -- no contacts or calendaring the last time I checked. There's also Emoze, Seven, etc.
Check this great thread about the different email clients for S60: [http://www.howardforums.com/showthre...p-T-XpressMail]
You can still use the E71 to connect to Wifi even if your phone is missing a sim. There should be a profile called offline.