We produce Live webcasts of events and what you are saying your requirements are go beyond a simple camera.Â
for Camera I would suggest a good quality 3 CCD camera. Budget will determine what you go with but I love our XL1s' and with the MA200 we can put in multiple XLR mic's. Will go on standard tripod and can be bought for decent value IMO. We also have a Sony DSR250A. Again little older but good quality camera that perfroms well. Downside to Sony is the baseplate and tripod requirements add to the cost. But the sony does have built in XLR so saves you on the cost of MA200
We use 4 cameras in our prodution so we also have a cheapo MX1 video switch. It does the job for us, has chroma key,couple of hundred transitions and some features I yet to figure out. Apparently it has Luminance that will allow you to plug in computer and use graphics as video source but I have yet to try it. depending on what we do for graphics generation I may go with an MX4DV for our next event if budget will permit the purchase
We run all our audio through a Behringer 1204fx mixer. I like this mixer as it has some audio effects built in and comes with a USB type adapter to feed audio from mixer to computer. Allows ontrol of audio and effects on each channel so you can control each mic independantly
 Lighting I can not really comment on as most our events are outdoor and cover a large space that would be to hard to light.
Software
Currently use Premiere pro CS3. Only really use this as it came with the suite we bought for photoshop and illustrator.Â
WEBCAM MAX. I know most people are probably groaning at this app. but for the price it allows me to do a variety of overlay effects with text and graphics on the downstream side of things. As well I can throw in images and other media files into the webcast easily. I am hoping to move away from it by getting a proper genreator to plug into the stream but for benig on a budget and needing to add some stuff to your webcasts it works. Again we are talking webcasts not production TV
The only other thing I can offer is cables. Buy more than you think you will need. Every event we seem to have a need for a different/longer/modified cable. Everything from S-Video, BNC, XLR have spares and more than enough length.