As I'm over in the UK at the moment and moving about a bit, I definitely needed mobile broadband.
I got T-mobile web'n'walk Plus for £20 per month, with a free USB modem and 3GB a month usage (which I have never reached), I opted for that one because it was cheaper than Vodafone (by a long way) and faster (in the south of England) than Three, plus they're going to upgrade the network to support download speeds of upto 7.2 mbps by the middle of 2008 for no extra charge.
At the moment I can get a maximum download speed of about 1.3 mbps and an upload speed of about 0.4 mbps anytime of the day, this is faster that some of my friends wired broadband speeds.
The selling point for me is of course I can surf the internet at broadband speeds anywhere, on the beach, in the library, on top of a mountain, etc, but also the fact that when you move house there's no disconnection charge and then you're forced to take out a new 12 month contract.
Overall I totally recommend it.
P.S. A word of advice, before I got the above, I got the Sony Ericsson W910i mainly to be used as a USB modem, what I found was that it could only manage a maximum download speed of about 0.7 mbps and an upload speed of about 0.3 mbps which to me was unacceptable so I cancelled the phone contract within the 14 day period.
Hope that helps. As for your site, could you not add the Three packages as well.