For me, bog standard small flake shavings, made into a deep litter bed at the back 2/3rds, rubber matting at the front. Easy to look after, stays sweet smelling all the time, deep and warm, surprisingly little to take out, ned loves to crash out for a snore in it and as an added bonus, my 3 "sponsored" rescue chickens Sage, Onion and Tikka Masala, love mooching about in it pecking up crumbs lol! We have to negotiate the odd pheasant and peacock on hacks so I like Sunny to be ok with feathery things pecking round his feet!
I really like flax. I work full time, and because the flax is so absorbent you only need to take the wet out once or twice a week (you can deep litter it but I've never liked that method). It also rots down well for manure.
I'm afraid there is no such thing as 'Best Bedding', it all depends on your horse, your stable & the lifestyle you & your horse has. Wether your horse is wet, messy, just uises one area, mixes everything into the bedding etc. It's a case of different bedding for different situations. You'll probably read a dozen different posts on which is best......... & you'll be no further forward.
Ive got 2 horses with very different habits in the stable but both very mucky, and have tried them on shavings and straw but have concluded that hemp (Aubiose) is the best for both of them.
Its just so much more stable so much more supportive and helps to stop kicking around the poo (the 17 hander) and so absorbant ( the wee-y 14.2 mare). Much quicker to muck out as just take out the poop most days, you cant even see/find the wet as its all at the bottom, take all the wet out every week or 10 days, no smell at all in the interim. Makes good compost v quickly and pour it out the bag.
So even tho I could get the straw for virtually nothing, and aubiose is £10 a bag, its still worth it. I put in 1 bag a week for each horse.
I've just discovered Sundown red, gave up on straw as my mare pigged it all - its a mixture of shavings and chopped straw and smells of eucalyptus (sp!!) - i really like it, it goes a lot further than your average bale of shavings, and its chunkier - i don't really like shavings as they tend to blow around all over the place. I put down a whole new bed and only used 3 bales - I pay £7.30 a bale so compared to shavings about a £1 saving and use a lot lot less!