In-home wireless vs. mobile broadband

mklickman writes: "I've been hearing more and more about mobile wireless broadband offered by the big wireless phone providers, and for the first time came to ask myself a very interesting question. Since my wife and I both have laptops, and we're out a lot (she's a photographer and I'm a graphic design student) would it be wise and/or worth it to do away with the standard cable-internet-plus-modem-plus-router setup and switch over to mobile-broadband-PC-card-only mode, a la AT&T or Sprint? I've looked into pricing and stuff a bit, and I'm not really concerned about the cost of the PC cards themselves; they're not much more expensive than a decent router. Also, the cost of the wireless service per month is only (roughly) ten dollars more than my current ISP is charging me. Is it a good idea?"