I first played this game a few years ago, and after seeing the Hobbit got back into it. Trying to choose a race and class, combined with rereading the Hobbit and the Lord of the Rings, got me thinking about the most suitable classes for each race. I don't intend to start any old arguments about certain classes, just to find out what classes the books support. My thoughts so far:
Burglar - based on Bilbo of course, also the statement in the Hobbit that hobbits are excellent at moving silently, love riddle games etc.
Minstrel - rereading the Fellowship of the Ring, the hobbits place a lot of importance on songs and music to keep their spirits up.
You could argue Warden, based on the Bounders of the Shire, but there are only 12 of these in the whole Shire.
Minstrel - I'm thinking of the Elves described in the Hobbit, who always seem to be singing and having fun. That's their depiction in this story of course, but still.
Loremaster - based mainly on Elrond of Rivendell, with reading runes, commanding the water at the Ford of Bruinen, that kind of thing.
Hunter - based mainly on Legolas.
Warden - I understand this is based on Haldir of Lorien.
Burglar - based on Grima Wormtongue mainly, sneaking around, stealing people's items. Also people such as Bill Ferny.
Captain - Eomer, Faramir - the men of Middle Earth clearly value leadership and inspiration. Also Aragorn himself of course.
Champion - mainly thinking of Boromir here, who emphasises combat and battle.
Hunter - based on the Rangers, also Faramir's company who attack the Southrons. Also possibly the men of Dale, as Brand himself was an excellent archer.
Guardian - the dwarvish characteristics of toughness and defiance seem to support this, as well as Gimli taking up a shield at the Battle of Helm's Deep.
Champion - based on Gimli, also the Hobbits of Thorin's company whose first thought when Bilbo discovers the gap in Smaug's armour is how best to fight him and kill him.
I'm certainly not a (Tolkien) lore master myself so please let me know your thoughts and corrections.