Let's keep to legal topics please. I'd appreciate self edits.
As for what to bring, depending on your goals, you may or may not have a lot of time to converse and swap. If this is your first meet ever, I would highly suggest using your time efficiently and listen to as much gear as possible. This will arm you with knowledge for the year between meets. The more meets you attend the less of a shotgun approach you need to take. You can focus on new products, gear you like and synergy combinations. There's lots of opportunity to chat, but before you get yourself in a 30 minute discussion about rig xyz make sure you've listened to anything present that might compare. You will regret it later, trust me!
If you aren't so serious about getting the most gear experience for your meet time, feel free to gab it up, listen to lots of different music and help yourself to the snacks and spirits and relax with the crew. Listen to the gear you really need to but enjoy yourself and your company.
Either approach is perfectly fine. I am most certainly in the first group, but a good meet will have a mix of both and some straddling the fence.
I would highly suggest making a demo cd with 320k/s mp3 or better tracks of music you've listened to hundreds of times that highlight different aspects of headphone performance. If you have vinyl that fits this bring it also since we appear to have several turntables this time. Bring a small notebook, say 50-100 pages 4x6 or so to make notes. By the time you get home you will have forgotten much of what you've heard. Make notes you can refer to later.
To all people bringing snacks, since we are not breaking for lunch or bringing any in, please try to have snacks with substance, rather than everyone bringing candy or cookies. Some is great, but we'll be bouncing off the walls towards the end of the meet if all we have is sugar.
If you are displaying gear make sure you have a power strip capable of powering all of your gear. If you have small extension cords I would suggest bringing them in case they are needed. If you are showing gear please indicate in the thread so I can have a table name plate printed up for you.
Since I'm on my soapbox I might as well mention hygiene and respect of others property. Clean your ears, hair, face and hands (and the rest of you) before attending. Avoid styling gels and cremes, etc that can get on peoples headphones. Treat others items better than your own. If you would like to change the headphones connected to an amplifier but you are not completely familiar with it, please ask the owner. Some amps like to be off, or turned down before changing. Don't hesitate to ask if you can try a piece of gear, even amp or source from someone's rig in your own, but be respectful if they decline (and if you are the decliner, be nice when doing so). Records are very fragile and misshandling can make them dirty and scratched. If you don't know how to handle them, ask for help. Gear should be marked with the owners name and username by the table badges I'm making so there is no excuse not to ask.
Also, I believe this meet will have food and drinks outside, keep them there or at least a good distance from any gear. You really don't want to pay to replace someone's gear or the carpet in the room.