I've did a similar project, recording analog sensor data for watering my garden. Just take a look at http://maslestorres.cat
But I'm process of updating the datalogger part with v2.0:
v1.0 - arduino UNO + XBee shield, tied via USB/serial to a computer with sqlite and a Objective-C development to save data in a Mac mini.
v2.0 - arduino Mega + XBee shield with RTC and SD + Display. Autonomous unit but when connected to the Mac mini saves data to sqlite. Objective-C code handling serial data replaced by a phyton script which is by far simple and powerful.
v3.0 - I'm just thinking about it... Raspberry PI with sqlite, but how to get XBee data ? Arduino Yún ?