I do quite a bit of freelance photography so I like to show the client my website which has a lot of photos so it eats up a lot of data. And off the record I like tethering for those times I'm on the road now, after I updated to 3.0 🙂
Since I can't stream music on my work PC, I've become a hardcore Pandora and Shoutcast app user over 3g. My monthly use has gonne from about 400 MB to about 1.5 GB
I usually try and max out my data cap on my plan. Went from 500MB to 1.1GB limit with 3gs upgrade. To get to 1.1GB will probably require tethering. 🙂
Australian carriers, all have data caps...
But also since I have gotten my uverse with a new router I use my wifi quite a bit more than I used to. My wifi didn't even cover my small house all the way before and I would use edge in my dining room.
I use between $19,000-23,000USD worth of data per month, according to my carrier. Of course, that's adjusted down to about $50 (flat-rate data) ... In terms of MB, I think it's only about 300MB/month. Not that much, really.