Dave,
I do design hardware from time to time but yeah, I'd love to do more. I tend to use SPI as I think it's both easier and faster and all the functions you mention are available in chips with SPI-interface as well as I2C so I've never actually had the need TO use it - that's it really.

Scampy,
I2C/Read/Write are not "hardware assisted" commands, they do not use the (M)SSP module in the PIC so any pins can be used.

picmilan,
I'll repeat what I said earlier: Check if the pins you're using has analog functions and make sure they're turned off.

/Henrik.