We put a good sized pre-brined corned beef in a crock pot, cut a head of cabbage into quarters, then halve the quarters (yes, that's eighths, but little wedges, not slivers).
Then we add carrots and potatoes, the latter cut into quarters. And we add that little spice packet too. We just cover with about a cup of water to keep it moist, but a
I thought I'd link you to some more recipes. That way you can choose your own special version. The lovely picture here came from allrecipes.com It's the top rated recipe on the web.
Another top recipe is Alton Brown's at foodnetwork.com Don't you just love his recipes. Usually easy, and delish. This one includes a recipe for brining if you choose to do your own.
Here's another foodnetwork recipe for Corned Beef and Cabbage. This one is cooked in the crock pot but has a tasty Horesradish sauce.
Hope these help you prepare for the feasting, and don't forget to keep your dark Irish beer at room temperature.
After posting I realized I left out you vegans, sorry. Here is a recipe with make your own vegan meat. Here's another using seitan. Others basically the same recipe as the meat, but using meat substitute.