use SMS backup+, this app always backup our sms & call logs to gmail account, never worry about you SMS's, even if you phone lost or accidentally deleted any sms, you can see the all the messages from your gmail account.
also you can restore from backup when you buy a new phone or whatever.
its a life saver app
and Polaris office + PDF - this app will open all office docs and pdf's , i don't know its free or not, but its came with my HTC phone.
as a fiverr user this app helped me lot