Painting raised beds........

Afternoon all, hope the sun is out wherever you may be.
Right.....still not on my plot, the guy who has it is in no hurry to remove his bits and bobs...but hey ho, I can wait.
Anyway, I'm knee deep in my planning and design stage....I'm planning in using raised beds within the plot..and I'm just wondering...what is the best treatment to use on the wood that will form the beds? Just so I can start pricing bits and pieces up,
Thanks in advanc

Tony

Mine are made of gravel boards and are just crates really, within which are polypropolene bags for the veggies.

I decided to go all arty with them and have got a variety of cuprinol colours.  The salad area is all willow green; the veg. planters will be old english green; the spud planters lavender or forget-me-not.  As we grow at home, it's nice to look out of the kitchen window onto it all.  The rest of the fencing around the place and the new hen house is just normal wood preservative in oak colour.  The coloured paints were pricey but Homeb*** had an offer on a few weeks ago, so I got it then.  The henhouse stuff was ultra cheap, but good quality from H***bargains. 

Just enjoy it all!