Here I go - the single biggest thing I will buy to take on The Big Trip (in more ways than one..), so there will be plenty of posts on my developing thoughts in this area.

Initial recommendations seem to suggest MacPac is a quality range with the Orient Express looking good, and I also like the look of the Karrimor Global 50-70. Haven't gone to a shop to actually poke and prod the things yet - will post results when I do.