This is my first post...sorry if it's a little lengthy. I have been asked to take pictures for a corporate holiday party for approximately 800 people. They want both "party pic" type pictures, as well as a mini-studio in a corner of the room for formal, posed shots. I am looking for advice for the following situations: 1. Party pics: I've done many party-pic events before, but not with this equipment. I believe I am relatively well-equiped (canon 20d, 17-40f4 L, 580ex, strobofram proT bracket, two 1gb x80 cf cards, and 8 rechargeable lithium ion batteries). Do you think the batteries are enough, or should I pony up for a quantum battery pack? (or rent one?) Also, if I want to use any or all of the party pics on my website (other than for re-sale to the event participants) do I need releases? If so, how would I do that in a loud, fast-moving, party environment? 2. Location-studio pics: I currently have a backdrop stand and two monolight strobes (Photogenic), also a 70-200f4 L and a bogen 3021bpro/3030 head tripod. I've used this set-up before in my basement "studio", and can use one light on either side of the camera with either umbrellas or soft-boxes. My question here is would you also recommend a small light to light the backdrop? Any other lights? Obviously, the simpler the better. Also, what would you recommend for a backdrop? Paper? Muslin? Black? White? Color? Also, should I ask each couple to fill out a quick name/addrss/phone/email card to use in either future marketing efforts or in case I want to use the picture and need to contact them for a signed release? (Which begs the question I asked above - do I need a release to show these photos un-protected on my website?), or is that asking too much from the young, party people? Thanks in advance for any advice you can give!