There are so many good boards out there. each brand has some good boards and bad boards.
burton are nice boards. i find they are really nice to ride straight away but sometimes have a tendancy to fall apart quickly. they are also mass produced so can be a bit cheaper than most and easy to find. stay away from the vapour . the aluminium core sometimes warps and there is very little stance width adjustment. plus they are really expensive.
nitro are really good. i think their best boards are the freestyle range, mfm, t1, t2 t0 etc.
for powder boards i ride nidecker. thier megalite is the best pow board ever!! it rides powder like most boards ride groomers.
the lib tech magnetraction is awesome if you ride alot of ice and variable conditions. the edge design give s you pretty good grip even in gnarly conditions. it doesnt make much difference in pow and the edges sometimes hang up on jump lips when taking off for a spin and boardsliding plastic stuff.
k2 have some nice boards as well. i havent tried it yet but alot of my riding buddies think the darkstar is the best freestyle board ever!!
other brands that i have heard good things about are atomic, stepchild and ride.
Really the best brand is a personal preference cos everyone needs something different in a board. try and demo lots of boards and find what you like. think about what type of riding you want to do and cater your board for that.
Good luck!!