Any broadband connection should give you enough bandwidth. Remember that although you can easily get more downstream bandwidth by paying more money, your upstream bandwidth (which determines how fast you can send data) is usually fixed at at much lower rate - 256kbit or 340kbit perhaps. So upgrading to a 10mbit downstream connection won't improve things at all.
Software is easy, Skype.
Webcams are a personal thing; personally I like Logitech. For decent audio quality you need a headset too. You could do worse than this package.