I've tried, used, and broken a lot of gear over the years. The checklist below serves as a guide for the gear I pack on backcountry snowboard day trips. Of course, if you are doing over nighters or multi-nighters you would opt for a larger pack and include items like your thermarest and sleeping bag. The gear below has always worked great for me and it's dealt with my abuse well. I use this stuff 2-3 times a week and it never lets me down.
SNOWBOARD - Unity Origin, or Capita Swallow Tail for the steep and deep. Make sure the board securely fastens to your backcountry pack.
http://unitysnowboards.com
http://capitasnowboards.com
SHOWSHOES - Use to break trail in deep snow, useful for long slog approaches. Break these out when you start to post hole. Purchase largest size available, I use ATLAS 1230. Rated at 175lbs - 250lbs.
http://www.atlassnowshoe.com/products/
BACKCOUNTRY PACK - Osprey switch 25+5 backcountry snow pack. With this pack you can keep your shovel assembled and have easy access to your probe and snow study gear.
http://www.ospreypacks.com/
TREKKING POLES - Get something light and adjustable. You'll use these alot
during slog, ascent, and snowshoeing. Make sure they attach to your pack. I use Leki Ultralite Ti Air-Ergo.
http://www.leki.com
SNOWBOARD BOOTS (crampon/snowshoe tested) - I use ThirtyTwo 304s because
they fit my snowshoes and work perfectly with my CAMP crampons. Solid boot and does well hiking backcountry or talus fields.
CRAMPONS - Buy something solid that will last and make sure they work with
you existing snowboard boot. I use CAMP. They strap on to my snowboard boots vs. models made to fit hard alpine touring boots.
http://www.camp-usa.com
ICE AXE - At least 60cm, I use the Black Diamond Raven 65cm. Pick yourself up a self arrest and ice axe leash (learn how to self arrest).
http://www.bdel.com
AVALANCHE BEACON - BCA Tracker, digital beacon almost walks you to the victim. Learn how to use it along with your probe and do practice tests with you group before you leave trailhead. Don't trust new BC partners, show them you can find a beacon and have them show you. Its your life.
http://www.bcaccess.com/bca_products/tracker/index.php
SHOVEL - BCA shovel for digging out victims and doing snow profiles. Some BCA shovels come with a probe that stores inside the shovel, these probes are generally too short for deep burials.
http://www.bcaccess.com
PROBE - BCA probe, collapsable and stored in side your shovel or snow saftey section of your pack. 300mm or longer is best for deep snow.
http://www.bcaccess.com
SNOW STUDY KIT - Inclinometer, termometer, snow crystal cards, profile
cheat sheets, ruetschblock cord.
http://www.rei.com
WATER FILTER - MSR waterworks EX, attachs to osprey pack bladder. If using in exterme cold, disassemble after use and blow out remaining water.
http://www.msrcorp.com
PETZEL HEADLAMP - 2 beam focus lamp, light, extra batteries.
http://www.petzel.com
MOTOROLA RADIOS - Communication is essential in the backcountry. The talkabout series works well, lots of people have them. 7 mile radius.
http://www.ebay.com
GPS MAP60CS - GPS with current destination topo uploaded, parking area and waypoints marked. Extra batteries for GPS.
http://www.garmin.com
FIRST AID KIT - Basic REI kit. I include smelling salts, space blanket, weather proof matches, iodine tablets, compass, fire paste.
http://www.rei.com