Besides, all the good suggestions above, here's another:
If you don't have a I2C to Parallel converter for your LCD display, you can always use a 74HC595 and send data serially to the LCD. In this scenario, the 74HC595 will work as a "serial to parallel" converter, and you'll only use 3 pins to interface with the 595. There are several articles in the web that will teach you how to interface with a HD44780 display.
The 595 is a lot cheaper and just as easy to implement than the i2c adapter. When working with a LCD display, the 595 will allow for slightly display updates, but not nearly as fast as the native parallel implementation.
On a side note: I am a HUGE fan of the 74HC595 when it comes to Arduino projects. Basically it works as a port multiplier and a serial-to-parallel converter (for digital pins), although officially its description is "8-bit Shift Register". There are plenty of libraries available for the 595, be it running dual motor drivers, LCDs, etc, which proves it is useful for all sorts of projects. Besides, it is extremely cheap (in the cents range).