That's a lot! I do sometimes play Sudoku on my Nokia when at uni, but that's just rare occasions. I send 3-5 SMSes per day max, and talk from time to time... I'd say about 10-15 hours per month, LoL, if not less.
I only use my cell phone for a couple hours for the whole month. If I used it that much every day I would not be able to afford the bill. I mostly use my home phone as I have unlimited long distance on there!