depends what sort of boarding you want to do...general mix, only downhill or parkland stuff (stunts).
I'm a big heifer who can't jump so i've got a downhill board. I've got big feet too so have risers on the bindings so i don't catch my toes all the time. the board i have is a nitro, good quality stuff. i've got flow bindings which is a bit of a contentious snowboarding issue, a bit like the old curvy/pointy debate here (obviously flows are great and curvys are best)
may be an idea to go to a shop and fish for advice before buying second hand, although you may get a real good deal at a shop
have a dig about
http://www.snowboardclub.co.uk/ that is full of useful info and discounts if you join up, has a good forum too